Bash Utilities

utils.sh

#!/bin/bash

(( 0 )) && {	# 

	echo
}
(( 1 )) && {	# 

	# Something of a shot in the dark, but when we had a server with a high 
	# load average where nothing obvious was causing it, it turned out to be
	# multiple df cmds hanging on a stale nfs mount. This command helped us id it:

	top -b -n 1 | awk
		'
		{ if (NR <=7) print; else if ($8 == "D") {print; count++} } 
		END
		{print "Total status D: "count}
		'
}
(( 0 )) && {	# entropy stats.  WHOLE NUMBERS ONLY

	for F in /data/ja/logs/entropy.black
	do
		TALLY=$(cat ${F} |wc -l)
		echo "Tally of entries: ${TALLY}"

		CUM=0
		SUM=$(cut -d' ' -f10 ${F} |while read N; do CUM=$((CUM + N)); echo $CUM;  done |tail -n 1)
		echo "Sum of entries: ${SUM}"

		AVG=$((SUM / TALLY))
		echo "Average of entries: ${AVG}"

		# just use the values
		G=${F}.values
		cut -d' ' -f10 ${F} > ${G} 

		# Standard Deviation
		
		while read N
		do
			DIFF=$((AVG - N))	# difference between mean and data point
			DIFSQ=$((DIFF * DIFF))	# DIFF squared.
			SUM2=$((SUM2 + DIFSQ))	# sum of squares.

		done < ${G}
		AVG2=$((SUM2 / TALLY))		# average of sum of squares.
		SDEV=$(echo "scale=3; sqrt($AVG2)" |bc)
		echo "Standard Deviation: $SDEV"
	done

}
(( 0 )) && {	# simulate typing the text in a file.

	SLEEP=0.05
	head -n 7 /data/ja/temp/spread/free_exchange.txt |while read LINE
	do
		#echo "$L"
		LEN=${#LINE}		# length of line
		LEN=$((LEN - 1))	# the substring command is zero-based.

		for N in $(seq 0 $LEN)
		do
			echo -n "${LINE:$N:1}"	# substring starting at $N of lenght 1. $N is zero-based.
			sleep ${SLEEP}
		done
		echo
	done
}
(( 0 )) && {	# identify credit card payment for the last 120 days.  Useful for new credit card number.

	# Sign-on to usaa site; goto credit card page; select 'last 120 days'; copy-paste data to new text document.
	# eg F=/data/ja/temp/spread/usaa.last.120.txt

	cd /data/ja/temp/spread/
	sort usaa.last.120.txt |uniq |grep '^[A-Z][A-Z]' |grep -Ev '^PAYMENT|^PENDING' > usaa.1

	# usaa.1 will contain 1-time charges and recurring charges.  there may be minor duplicates in usaa.1
	# tentatively, the following are recurring:
	#
	# AT&T *436097291116 08003310500 GA
	# AT&T*BILL PAYMENT 08003310500 TX
	# CLARK PEST CONTROL 209-3687152 CA
	# NETFLIX.COM NETFLIX.COM CA
	# WWW.1AND1.COM TEL8774612631PA
}
(( 0 )) && {	# create an md5sum for the files in a dir.  ? detect bit-rot

	find -type f -not -name md5sum.txt -print0 \
		|xargs -0 md5sum \
		>> md5sum.txt
}
(( 0 )) && {	# get disk info by path, uuid, id, 

	for P in path uuid id
	do
		ls -l /dev/disk/by-$P/ |sed -e 's;^total.*; ;'
	done
}
(( 0 )) && {	# which services do NOT have a lock file?

	# look in each init script for a line like: ^LOCK /var/lock/subsys.
	# if not found, then the script does not manage lock files.  Bad script, bad script.
	for i in /etc/init.d/*
	do
		grep -q /var/lock/subsys $i || echo "$i@Does not manage lock files."

	done |column -ts@	# nice formatting!
}
(( 0 )) && {	# parse config.rh6.functions.  use an array to hold line numbers of functions.
		# NB: this avoids the use of 'while read' which removes spaces, tabs, etc.
		# this requires a manual edit of config.rh6.functions.sh to remove all except the functions.

	cd /data/ja/bin/config/rh6

	F=l.config.just.functions
	[ ! -f $F ] && echo "Not a file: $F" && return

	TALLY=$(wc -l $F |cut -d' ' -f1)
	ARR=( $(cat -n $F |grep '(){' |tr -s ' ' |sed -e 's;^ ;;' -e 's;\t.*;;') )	# store the line numbers as an array.
	LAST=$(( ${#ARR[@]} - 1))

	for i in $(seq 0 ${LAST})
	#for i in $(seq 0 2)
	do
		#echo "${ARR[$i]}"
		DIF=$((${ARR[$i+1]} - ${ARR[$i]}))		# Line number diffs between consecutive functions
		[ $DIF -lt 0 ] && TT=$((TALLY - ${ARR[$i]}))	# ${ARR[$i+1]} does not exist.  => zero => dif is negative. so, redo dif.
		[ $DIF -gt 0 ] && TT=$DIF			# there is a function body, => dif is positive.
		#echo "${ARR[$i]} $TT"				# qc print: line-number of function, number of lines in the function.

		tail -n +${ARR[$i]} $F |head -n $TT > ttt	# extract the function to temp file.
		FN=$(head -n 1 ttt |sed -e 's;..{.*;;')		# grab the function name
		(
		echo '#!/bin/bash'
		echo
		cat ttt	|sed -e 's;^.*(){;do_it(){;'		# replace function name with do_it
		echo
		echo 'do_it'					# call do_it
		echo 'exit 0'
		echo "# Previously this code was function $FN in config.rh6.functions"
		echo
		) > $FN
	done
	[ -f ttt ] && rm ttt
}
(( 0 )) && {	# get info from a CD or DVD.

	blocksize=` isoinfo -d -i /dev/sr0 | grep "^Logical block size is:" | cut -d " " -f 5`
	blockcount=`isoinfo -d -i /dev/sr0 | grep "^Volume size is:" | cut -d " " -f 4`
	echo "   Blocksize: $blocksize"
	echo "  Blockcount: $blockcount"
}
(( 0 )) && {	# process a file with spaces in some lines.

	T=/data/ja/temp/TTT
	echo -e "Line_one\nLine two\nLine_three\nLine four" > "${T}"

	while read L; do echo "${L}"; done < "${T}"	# works.
}
(( 0 )) && {	# show progress within the 'less' pager.  see 1 below.

	VISUAL=0	# provide visual feedback to screen.
	for N in {0..202}
	do
		VISUAL=$((VISUAL + 1))
		[ $((VISUAL % 20)) -eq 0 ] && printf "Count: %3d\n" "$VISUAL"
	done
	printf "Count: %3d\n" "$VISUAL"
}
(( 0 )) && {	#  show progress at the cli.  NB: using 'less' will not work.

	echo -n '   '	# 3 spaces
	for N in {0..11}
	do
		printf "\b\b\b%d" "$N"
		sleep 1
	done
}
(( 0 )) && {	# sort on character position. Use fixed width, with WITH spaces.

	T=$(mktemp /tmp/sorting.XXXXXXXXXX)

	cat > $T <<-ENDOFSORTLIST;
	1134 0 1250
	1233 0 1240
	1332 0 1230
	1431 0 1220
	1530 0 1210
	1124 0 0160
	1223 0 0150
	1322 0 0140
	1421 0 0130
	1520 0 0120
	ENDOFSORTLIST

	echo -e "\n===== Numeric sort"
	sort -n $T

	echo -e "\n===== Numeric sort on positions 3-4"
	sort -n -k1.3,1.4 $T						# works.
	echo -e "\n===== Numeric sort on positions 1-2"
	sort -n -k1.1,1.2 $T
	echo -e "\n===== Numeric sort on positions 1-2 and 9-10"
	sort -k1.1,1.2n -k3.3,3.4n $T					# does not work.
	echo -e "\n===== Numeric sort on field 1, 1-2 and field 3, 3-4"
	sort -t' ' -k1.1,1.2n -k3.3,3.4n $T				# Works. Note -t is a space.

	echo -e "\n===== Numeric sort on positions 1-2 and 10-11"
	sort -t \& -k1.1,1.2n -k1.10,1.11n $T				# Works. Note -t is a ampersand.


}
(( 0 )) && {	# sort on character position. Use fixed width, with NO spaces.

	T=$(mktemp /tmp/sorting.XXXXXXXXXX)

	cat > $T <<-ENDOFSORTLIST;
	113401250
	123301240
	133201230
	143101220
	153001210
	112400160
	122300150
	132200140
	142100130
	152000120
	ENDOFSORTLIST

	echo -e "\n===== Numeric sort"
	sort -n $T

	echo -e "\n===== Numeric sort on positions 3-4"		# Works
	sort -n -k1.3,1.4 $T

	echo -e "\n===== Numeric sort on positions 1-2"
	sort -n -k1.1,1.2 $T
	echo -e "\n===== Numeric sort on positions 1-2 and 8-9"	# Works.
	sort -k1.1,1.2n -k1.8,1.9n $T

	# NB: the above data is ALL ONE FIELD. So, use 1.1, 1.2, 1.8, 1.9 with a numeric for each sort key.

}
(( 0 )) && {	# have a delay.

	# sleep delay-in-seconds.
	echo $(($(date +%S)*3))		# seconds x 3.  0 thru 177 seconds.

	#
	echo $(($RANDOM % 45))		# 0 thru 44.

}
(( 0 )) && {	# Delete control characters in a file.

	# from: https://snipt.net/rqsall/delete-control-characters-in-a-file/
	tr -cd '[:print:]\n' < filename > newfile
	# Thanks to "command line magic" on twitter, follow 'im.
}
(( 0 )) && {	# install or update calibre.  does NOT use Distribution update mechanism.

	echo
	# get prompted for the install dir.
	#python -c "import sys; py3 = sys.version_info[0] > 2; u = __import__('urllib.request' if py3 else 'urllib', fromlist=1); exec(u.urlopen('http://status.calibre-ebook.com/linux_installer').read()); main()"

	# specify the /opt dir:
	# python -c "import sys; py3 = sys.version_info[0] > 2; u = __import__('urllib.request' if py3 else 'urllib', fromlist=1); exec(u.urlopen('http://status.calibre-ebook.com/linux_installer').read()); main(install_dir='/opt')"

}
(( 0 )) && {	# Is a drive USB?

	for DEV in ls /dev/sd[a-z]
	do
		echo
		echo $D
		udevadm info --query=all --name=$D |grep BUS=;
	done
}
(( 0 )) && {	# reserved space in file system.

	RBC=$(tune2fs -l /dev/sdb1 |grep '^Reserved block count' |awk '{print $4}')
	BC=$( tune2fs -l /dev/sdb1 |grep '^Block count' |awk '{print $3}')

	echo $RBC/$BC |bc -l |xargs printf "%1.2f\n"
	# prints: 0.05
	# ie: 5%
}
(( 0 )) && {	# Notes on locate and its configs.

	# /etc/cron.daily/mlocate.cron gets a list of 'nodevs': nodevs=$(< /proc/filesystems awk '$1 == "nodev" { print $2 }')
	# on CentOS 6.3 there are 26 items in the list, including devtmpfs.

	# /etc/updatedb.conf has 4 variables that specify different ways to prune the 'locate' process.
	# the PRUNEFS variable contains 'nodev' name, like nfs or nfs4 or tmpfs; a total of 46 items.

	# some items are on both lists, eg: tmpfs proc nfsd fuse
	# some items are on only 1 list, eg: nfs4, nfs, iso9660, ecryptfs, ...
	# those singletons come from both lists, so, both lists are needed to fully specify the exclussions.

	echo
}
(( 0 )) && {	# from http://www.catonmat.net/blog/tcp-port-scanner-in-bash/

	scan() {
		if [[ -z $1 || -z $2 ]]; 
		then
			echo "Usage: $0 <host> <port, ports, and/or port-range>"
			return
		fi

	host=$1
	ports=()
	case $2 in
		*-*)	IFS=- read start end <<< "$2"			# This might be useful.
			for ((port=start; port <= end; port++)); 
			do
				ports+=($port)
			done
			;;

		*,*)	IFS=, read -ra ports <<< "$2"			# Ditto.
			;;

		*)	ports+=($2)
			;;
	esac

	# NB, peter uses /dev/tcp which is not available on CentOS
	for port in "${ports[@]}"; do
		alarm 1 "echo >/dev/tcp/$host/$port && echo \"port $port is open\"" || echo "port $port is closed"
  done
}

}
(( 0 )) && {	# Monitor network connections.  Assumes raw data file exists.

	# Raw data file generated: 
	# eg: date ; time for X in {1..7200} ; do ss -apt     >> raw.N ; sleep 1; done
	# or: date ; time for X in {1..7200} ; do netstat -tp >> raw.N ; sleep 1; done  

	DIR=/data/ja/logs/ss
	REV=4
	RAW=${DIR}/raw.${REV}
	LOCAL=${DIR}/local_addresses.${REV}		# Local IP address
	REMOTE=${DIR}/remote_addresses.${REV}	# Remote IP addresses
	GROOMED=${DIR}/groomed.${REV}
	EXCLUDE=${DIR}/exclude.${REV}		# Exclude these remote ip address, since this are known local processes.
	> ${EXCLUDE}				# truncate $EXCLUDE

	egrep -v 'LISTEN|^State|:ssh|:nfs' "${RAW}" |uniq |awk '{print $5}' |cut -d: -f1 |sort |uniq > ${REMOTE}
	echo
	echo "There are $(cat ${REMOTE} |wc -l) remote ip addresses."

	# for each remote address, look at unique connections.
	#cat ${REMOTE} |while read IP; do echo; echo $IP; host $IP; grep $IP "${RAW}" |sort |uniq ; done
	# this would let me filter out some remove IPs

	# Or, change column order: 1,2,3,4,5,6 --> 4,5,6,1,2,3 and then sort on local ip address.
	cat ${REMOTE} |while read IP; 
	do 
		echo; 
		echo $IP; 
		host $IP; 
		grep $IP "${RAW}" |awk '{print $4 " " $5 " " $6 " " $1 " " $2 " " $3}' |sed -e 's;^192.168.1.20:;;' |sort |uniq > ${GROOMED}
		N=$(cat ${GROOMED} |wc -l)
		echo "There are $N instances of this remote ip address in ${RAW}:"
		cat ${GROOMED}

		# Can this remote ip address be excluded?
		#grep -q 'check_access.pl' ${GROOMED} && case $N in
		case $N in
		1)	grep -q 'check_access.pl' ${GROOMED} && echo $IP >> ${EXCLUDE}
			;;
		2)	# if both instances have check_access.pl, then add $IP to exclude list.
			[ $(grep -c 'check_access.pl' ${GROOMED}) -eq 2 ] && echo $IP >> ${EXCLUDE}

			# if only one instance has check_access, AND the local port numbers are consecutive, then add $IP to exclude list.
			PORT1=$(head -n 1 ${GROOMED} |cut -d' ' -f1)
			PORT2=$(tail -n 1 ${GROOMED} |cut -d' ' -f1)
			echo "Port 1: ${PORT1}"
			echo "Port 2: ${PORT2}"

			DIF=$((PORT2 - PORT1))
			[ $(grep -c 'check_access.pl' ${GROOMED}) -eq 1 ] && [ ${DIF} -eq 1 ] && echo $IP >> ${EXCLUDE}
			;;
		*)	# if any of these instances match 'clock-applet' then exclude this remote ip address.
			echo "clock"
			grep clock-applet ${GROOMED}
			echo "clock 2"
			grep -q clock-applet ${GROOMED} && echo $IP >> ${EXCLUDE}
			;;
		esac

		echo "Exclude these remote ip addresses:"
		cat ${EXCLUDE}
	done
}
(( 0 )) && {	# Put a message at the top of a file, then save to another filename.

	cat - "$repo" > "$repo".disabled <<EOF
# This is a yum repository file that was disabled by
# ${0##*/}, a script to convert CentOS to Oracle Linux.
# Please see $yum_url for more information.

EOF

	# Or, for a short msg:
	echo "Whatever" |cat - $somefile > $somefile.new.version
}
(( 0 )) && {	# Heading above the results of: /usr/bin/diff --side-by-side --width 160

	OLD=/data/ja/temp/etc.sysctl.conf.1
	NEW=/data/ja/temp/etc.sysctl.conf.2

	for n in $(seq 1 ${#OLD}); do EQOLD="${EQOLD}="; done
	for n in $(seq 1 ${#NEW}); do EQNEW="${EQNEW}="; done

	WIDTH=160
	HALF=$((WIDTH / 2))

	printf "%-${HALF}s%-${HALF}s\n" "${OLD}" "${NEW}"
	printf "%-${HALF}s%-${HALF}s\n" "${EQOLD}" "${EQNEW}"
	/usr/bin/diff --side-by-side --width ${WIDTH} ${OLD} ${NEW}

}
(( 0 )) && {	# Where are the biggest increases in Raw Read Error Rate ?
		# Use raw data, before grooming.
		# This has 5 minute intervals, so it may not seem to corrolate with the line chart, which used 1 houe intervals.

	F=/data/ja/logs/smart.oman.raw.read.error.rate
	T=/tmp/T

	grep -v ^# $F |uniq > $T		# remove comments
	PrevRaw=$(head -n 1 $T |cut -d' ' -f3)	# start with Prev equal to first Raw.
	#echo "PrevRaw: $PrevRaw"

	while read DATE SSE RAW
	do
		echo "$((RAW - PrevRaw)) $DATE $SSE $RAW"
		PrevRaw=$RAW

	done < $T |sort -rn |head -n 23		# the top 23 are GT 10m, FOR NOW.

}
(( 0 )) && {	# sar.  system accounting reporter.
		# Thanks: http://www.thegeekstuff.com/2011/03/sar-examples/

	# cpu usage.
	sar -u				# Displays CPU usage for the current day that was collected until that point.
	sar -u 1 3			# Displays real time CPU usage every 1 second for 3 times.
	sar -u ALL			# Same as “sar -u” but displays additional fields.
	sar -u ALL 1 3			# Same as “sar -u 1 3″ but displays additional fields.
	sar -u -f /var/log/sa/sa10	# Displays CPU usage for the 10day of the month from the sa10 file.

	# cpu usage by core.
	sar -P ALL			# Displays CPU usage broken down by all cores for the current day.
	sar -P ALL 1 3			# Displays real time CPU usage for ALL cores every 1 second for 3 times (broken down by all cores).
	sar -P 1			# Displays CPU usage for core number 1 for the current day.
	sar -P 1 1 3			# Displays real time CPU usage for core number 1, every 1 second for 3 times.
	sar -P ALL -f /var/log/sa/sa10	# Displays CPU usage broken down by all cores for the 10day day of the month from sa10 file.

	# memory free and used.
	sar -r
	sar -r 1 3
	sar -r -f /var/log/sa/sa10

	# swap space used.
	sar -S
	sar -S 1 3
	sar -S -f /var/log/sa/sa10

	# Overall I/O activities
	sar -b

	# Individual block devices
	sar -d				# dev53-1 means a block device with 53 as major number, and 1 as minor number.
	sar -p -d			# -p means display the actual device name, eg: sda

	# report network stats.
	sar -n KEYWORD			# where KEYWORK is one of the following:
	# DEV – Displays network devices vital statistics for eth0, eth1, etc.,
	# EDEV – Display network device failure statistics
	# NFS – Displays NFS client activities
	# NFSD – Displays NFS server activities
	# SOCK – Displays sockets in use for IPv4
	# IP – Displays IPv4 network traffic
	# EIP – Displays IPv4 network errors
	# ICMP – Displays ICMPv4 network traffic
	# EICMP – Displays ICMPv4 network errors
	# TCP – Displays TCPv4 network traffic
	# ETCP – Displays TCPv4 network errors
	# UDP – Displays UDPv4 network traffic
	# SOCK6, IP6, EIP6, ICMP6, UDP6 are for IPv6
	# ALL – This displays all of the above information. The output will be very long.

	# Start time
	sar -s 10:00:01		# starts at 10 am rather that midnight.
}
(( 0 )) && {	# Compare each character of the password hashes for root, ja, elh, guest.

	# Hashes for each user.
	 ROOT=$(grep '^root'  /etc/shadow |cut -d: -f2)
	   JA=$(grep '^ja'    /etc/shadow |cut -d: -f2)
	  ELH=$(grep '^elh'   /etc/shadow |cut -d: -f2)
	GUEST=$(grep '^guest' /etc/shadow |cut -d: -f2)
	echo -e " Root: $ROOT\n   Ja: $JA\n  Elh: $ELH\nGuest: $GUEST"

	LEN=${#ROOT}	# length of hash.
	LEN=$((LEN -1))	# will be zero-based.

	for N in $(seq 0 $LEN); 
	do
		# If each corresponding character is equal, then print the four characters.
		[ ${ROOT:$N:1} == ${JA:$N:1} -a ${JA:$N:1} == ${ELH:$N:1} -a ${ELH:$N:1} == ${GUEST:$N:1} ] \
			&& echo -e "Position: $N\t${ROOT:$N:1}${JA:$N:1}${ELH:$N:1}${GUEST:$N:1}"
	done |less

	# prints:
	# Position: 0     $$$$
	# Position: 1     6666
	# Position: 2     $$$$
	# Position: 19    $$$$
	#
	# So, position 19 probably marks the end of the salt. ie: the salt has a length of 20.

}
(( 0 )) && {	# analyze recent selinux events.
		# thanks: Daniel J Walsh on CentOS list.

	# search thru audit.log for avc events that happened recently.  save to file.
	ausearch -m avc -ts recent > /tmp/mylog

	# analyze file.  This is similar to 'selinux -a /var/log/audit/audit.log'
	sealert -a /tmp/mylog
}
(( 0 )) && {	# find the cube root of a number.  Round to nearest integer.

	for N in 1 2 3 4 5 6 7 8 9
	do
		echo
		echo "N: $N"

		A=$((N*N*N))
		echo "Cubed: $A"

		B=$(eval "echo 'e(l($A)/3)' |bc -l")
		echo "Cube root: $B"

		echo -n "Integer: "
		eval "printf '%0.f\n' $B"
	done
}
(( 0 )) && {	# load monitor
		# thanks: John Doe, [email protected]  CentOS list.

	while :
	do
		LOAD=`cat /proc/loadavg | cut -f1 -d'.'`

		if [ $LOAD -gt 3 ]
			then ps auxfw > /tmp/ps.`date +"%s"`; sleep 60
		fi
		sleep 10
	done
}

(( 0 )) && {	# Stop the Caps Lock key.

	# the nested command prints "us"
	setxkbmap -layout "$(setxkbmap -print | awk -F + '/xkb_symbols/ {print $2}')" -option ctrl:nocaps
}
(( 0 )) && {	# Use the basename of a script as part of the tempfile or tempdir basename.

	for N in $0
	do
		TEMPFILE=$(mktemp "/tmp/$(basename $0).XXXXXXXXXX"); echo "Temp: $TEMPFILE"
	done
}
(( 0 )) && {	# get filesystem info, including superblock locations.  ext2 and ext3.

	# thanks: [email protected] on CentOS list.
	dumpe2fs /dev/sda1 |grep superblock

	# then use one of the backup superblocks:
	#e2fsfsck -b <number from above> /dev/VolGroup00/<logical volume>
}

(( 0 )) && {	# nmcli = network manager at cli.  Works on CentOS6

	man nmcli
	nmcli nm status
	nmcli con status
	nmcli con list
	nmcli dev list
	nmcli dev status
}
(( 0 )) && {	# 2 cols of info.  combine eg: admin ankush, amit

	# Sample input file.
	INFILE=~ja/temp/TTTT
	cat <<EOTx > $INFILE
               admin                      ankush
               admin                       amit
               powerusers               dinesh
               powerusers               jitendra
EOTx

	# Process input file.
	OUTFILE=$INFILE.out
	awk '{print $1 ": "}' $INFILE | uniq > $OUTFILE
	for GROUP in `cat $OUTFILE | cut -d ':' -f 1`
	do
		for NAME in `cat $INFILE | grep $GROUP | awk '{print $2}'`
		do
			sed -i "s/^$GROUP: /&$NAME,\ /" $OUTFILE
		done
	done
}
(( 0 )) && {	# generate a set of numbers

	sets=
	a=0
	b=0

	while [ $a -lt 2 ]  # 20 processes (and pipes)
	do
		while [ $b -lt 10 ]
		do
			sets="${sets}${sets:+ }$a$b"	# ${sets:+ } will add a space, if $sets exists and is non-null.
			echo $sets
			b=$(($b+1))
		done

		b=0
		a=$(($a+1))
	done

	echo $sets
	# prints: 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19
}
(( 0 )) && {	# For arin database only,
		# from: http://itools.com/tool/arin-whois-domain-search

	whois -h whois.arin.net n + 64.64.64.64
}
(( 0 )) && {	# phone related.

	# take samsung contacts export, remove photo info, then store as *.minus.images.vcf
	F=~ja/etc/var/contacts/Samsung/2011.08.13 ; grep ^[A-Z] $F.vcf |grep -v ^PHOTO > $F.minus.images.vcf

	# get full name (FN) and look for duplicates.
	F=~ja/etc/var/contacts/Samsung/2011.08.13.minus.images.vcf ; grep -h ^FN: $F |sort |uniq -c |sort -rn |less

	echo
}
(( 0 )) && {	# kill X server
		# by default, Control-Alt-Backspace will NOT kill X in RHEL6 and clones.

	# from [email protected] on Scientific Linux list.
	echo "setxkbmap -option terminate:ctrl_alt_bksp" >> ~/.profile
	# not tried yet.

	# Or, Using GNOME
	# - Get to the System->Preferences->Keyboard menu.
	# - Select the “Layouts” tab and click on the “Layout Options” button.
	# - Then select “Key sequence to kill the X server” and enable “Control + Alt + Backspace”.
}
(( 0 )) && {	# From rkhunter list, after finding hidden ports.
		# From Yago Jesus, developer of Unhide.

	# Warning: Hidden ports found:
	# ? ? ? ? Port number: 45812
	# ? ? ? ? Port number: 895
	# ? ? ? ? Port number: 900

	# First, to discover if it is a false positive, bind in the ports using necat
	nc -l 900
	nc -l 895
	# If you can bind nc to the ports, probably could be a false positive.

	# Next, try:
	netstat -tanp | grep 900
	# If you can't find it, is time to worry

	# Also, as root, try:
	lsof -i :900			# provides command, PID, user, ++
	fuser -n tcp 900		# provides PID

	# Then, ps -p PID
	# Better, to get more info:
	ps aux |grep -E 'USER|<PID>'	# provides user, PID, Start, Time, CommandName
	# the start time may be helpful. ??

	# John Horne suggested using strace on one of the found PIDs. Eg: strace -p 900
	# OP ran:
	strace -o traceout.txt -f unhide sys
	# which printed:
	# Found HIDDEN PID: 2446
	# Command: /usr/java/jdk1.5.0_11/bin/java

}
(( 0 )) && {	# use a hash to distribute many files over some dirs.

	# from R P Herrold on CentOS list.  This is /bin/sh
	CANDIDATES="pix00001.jpg pix00002.jpg pix00003.jpg"
	for i in `echo "${CANDIDATES}"`; do
		HASH=`echo "$i" | md5sum - | awk {'print $1'}`
		echo "$i        ${HASH}"
	done

	# A little simpler.
	echo
	CANDIDATES="pix00001.jpg pix00002.jpg pix00003.jpg"
	for i in ${CANDIDATES}; do
		HASH=`echo "$i" | md5sum - | awk {'print $1'}`
		echo "$i        ${HASH}"
	done

	# from Marc Deop, [email protected], on CentOS list.  This is /bin/bash.
	echo
	CANDIDATES=(pix00001.jpg pix00002.jpg pix00003.jpg)
	for i in "${CANDIDATES[@]}"; do
		MD5SUM=$(md5sum <(echo $i))
		echo "$i        ${MD5SUM% *}";
	done
}
(( 0 )) && {	# prevent firewall messages from being logged to the console

	# from [email protected] on CentOS list.
	# in sysctl.conf, set:

	kernel.printk = 3 4 1 7
}
(( 0 )) && {	# grep.  factor out common parts of a string.

	# how to get data from log files for a specified range of days? i.e 19-30 June 2011

	# from Owen Beckley on the CentOS list.
	grep -E '^Jun (19|2[0-9]|30) ' /var/log/messages

	# ja note.  Note the parens.  Its either/or within parens, but concatination outside parens.

	# man grep:
	# Repetition takes precedence over concatenation, 
	# which in turn takes precedence over alternation.  
	# A whole subexpression may be enclosed in parentheses 
	# to override these precedence rules.
}
(( 0 )) && {	# case statement with pattern matches.

	T=':::_and_more'
	T='::1:_and_more'
	case $T in 
	:::* )	echo colons	;;
	abc* )	echo abc	;;
	::1:* )	echo 'colon, colon, 1, colon'	;;
	* )	echo anything	;;
	esac

	exit
}
(( 0 )) && {	# bash " = " vs. "=" vs. "=="

	# From: [email protected] on CentOS list.
	# With the spaces around the '=' and the dollar before the variable
	# name this actually is a test not an assignment.
	# But using double '=' is more clear.

	C="no"
	if [ $C = "yes" ]; then echo "1: $C"; fi
	if [ $C="yes"   ]; then echo "2: $C"; fi
	# Print: "2: no"
}
(( 0 )) && {	# Run all "unhide" stardard and elementary tests.

	# "standard" tests.  the man page says that all elementary test are in the standard tests.
	for T in brute proc procall procfs quick reverse sys; 
	do 
		echo; 
		echo Test: $T; 
		./unhide-linux26 $T |egrep -v '^Unhide|^http|^$'; 

	done > log_of_unhide-linux26_standard_tests		# log is in ~ja/temp/download/unhide/unhide-20110113/

	# "elementary" tests.
	for T in checkbrute checkchdir checkgetaffinity checkgetparam checkgetpgid checkgetprio checkRRgetinterval checkgetsched checkgetsid checkkill checknoprocps checkopendir checkproc checkquick checkreaddir checkreverse checksysinfo checksysinfo2 ; 
	do 
		echo; 
		echo Test: $T; 
		./unhide-linux26 $T |egrep -v '^Unhide|^http|^$'; 

	done > log_of_unhide-linux26_elementary_tests		# log is in ~ja/temp/download/unhide/unhide-20110113/

	# Find hidden TCP/UDP ports
	./unhide-tcp ; echo $?

	# NB: maybe it's better to dump unhide output to a file,
	# then check the return value,
	# then filter the files.

}
(( 0 )) && {	# get a Short list of open files.

	lsof |egrep '^COMMAND|[0-9]w' |egrep '^COMMAND|/'	# Includes column names.
}
(( 0 )) && {	# Cronjob. A 65% chance of running. Then a random delay (LT 1 hour) before start.

	[ $(( $RANDOM \% 100 )) -lt 65 ] \
		&& sleep $(( $RANDOM \% 3600 )) \
		&& /path/to/climagic-poster.pl		# posts msgs to twitter.

}
(( 0 )) && {	# print the partition table.

	# Not easily readible but,
	#dd if=/dev/sda count=1 |od =tx1z	# shows current state in mbr.  Might have changed since last reboot.
	cat /proc/partitions			# Shows the partitions, as of the last boot.
}
(( 0 )) && {	# find artists w/o underscores. 1.

	# remove /data/mp3/, get artist name, get artist with the fewest tunes, 
	# ignore artists with _ in name, limit to 10, matching UC anything UC
	for A in AbbyLincoln AdamFaith AfiaMala AlHibbler AlienSexFiend
	do
		echo "${A}"		# Old name
		NEW=$(echo ${A} |sed -e 's;([a-z])([A-Z]);\1_\2;g')		# replace lowerUPPER with lower_UPPER
		echo "${NEW}"
		echo
	done
}
(( 0 )) && {	# find artists w/o underscores. 0.

	# remove /data/mp3/, get artist name, get artist with the fewest tunes, 
	# ignore artists with _ in name, limit to 10, matching UC anything UC
	for A in $(find /data/mp3/ -type f -print \
		|cut -b11- |cut -d'/' -f1 |sort |uniq -c |sort -n |grep -v '_' \
		|head -n 10 |awk '{print $2}' |grep '[A-Z].*[A-Z]')
	do
		echo "${A}"		# Old name
	done
}
(( 0 )) && {	# Using the PIPESTATUS array to display exit statuses of commands in the pipe

	#grep MemTotal /proc/meminf | awk '{print $2}'; echo "EXIT STATUS = ${PIPESTATUS[0]}"
	# prints: grep: /proc/meminf: No such file or directory
	# prints: EXIT STATUS = 2
 
	#grep MemTotal /proc/meminf | awk '{print $2}'; echo "EXIT STATUS = ${PIPESTATUS[1]}"
	# prints: grep: /proc/meminf: No such file or directory
	# prints: EXIT STATUS = 0}

	#grep MemTotal /proc/meminf | awk '{print $2}'
	#echo "grep STATUS = ${PIPESTATUS[0]}"
	#echo " awk STATUS = ${PIPESTATUS[1]}"
	# ${PIPESTATUS[1]} is empty.

	# Save PIPESTATUS array to a string.
	grep MemTotal /proc/meminf | awk '{print $2}'
	# echo -e "  Element 0: ${PIPESTATUS[0]}\n  Element 1: ${PIPESTATUS[1]}" # works.
	# echo "${PIPESTATUS[@]}"		# works.  number space number.
	P="${PIPESTATUS[@]}" ; echo "${P}"	# save as above
	for RETVAL in ${P}
	do
		echo "  RetVal: ${RETVAL}"	# works.
	done

	# Save PIPESTATUS array to another array.
	grep MemTotal /proc/meminf | awk '{print $2}'
	SAVE=( "${PIPESTATUS[@]}" )
	for N in $(seq 0 $(( ${#SAVE[@]} - 1)) )
	do
		echo "  Key: $N   Value: ${SAVE[$N]}"
	done

	## Apparently, the PIPESTATUS array must be used immediately.
	## IE, before another command overwrites it.
}
(( 0 )) && {	# Create a new array by removing elements from an existing array

	# Create an array
	A=( abe bob carl darla ellen fanny )
	LAST=$(( ${#A[@]} - 1))
	echo "  Last: ${LAST}"

	# Copy array A to array B and print each array.
	B=( "${A[@]}" )
	for i in $(seq 0 ${LAST})
	do
		echo "  A sub $i: ${A[$i]}"
		echo "  B sub $i: ${B[$i]}"
		echo
	done

	# Remove an element and print each array.
	unset B[1]	# ie unset bob
	for i in $(seq 0 ${LAST})
	do
		echo "  A sub $i: ${A[$i]}"
		echo "  B sub $i: ${B[$i]}"
		echo
	done

	# Remove another element and print each array.
	unset B[4]	# ie unset ellen
	for i in $(seq 0 ${LAST})
	do
		echo "  A sub $i: ${A[$i]}"
		echo "  B sub $i: ${B[$i]}"
		echo
	done

	# print just the existing elements in B.
	for EL in "${B[@]}"; do echo ${EL}; done

}
(( 0 )) && {	# Remove elements from an array

	# Create an array
	A=( abe bob carl darla ellen fanny )
	LAST=${#A[@]}
	echo "  Last: ${LAST}"

	# print array
	STR=''
	for i in $(seq 0 ${LAST})
	do
		if [[ ! -z ${STR} ]]; then STR="${STR} ${A[i]}"; else STR=${A[i]}; fi
	done
	echo "  Str: $STR"	# prints: "abe bob carl darla ellen fanny"

	# Remove an element and print array.
	unset A[1]	# ie unset bob
	STR=''
	for i in $(seq 0 ${LAST})
	do
		if [[ ! -z ${STR} ]]; then STR="${STR} ${A[i]}"; else STR=${A[i]}; fi
	done
	echo "  Str: $STR"	# prints: "abe  carl darla ellen fanny"

	# Remove an element and print array.
	unset A[4]	# ie unset ellen
	STR=''
	for i in $(seq 0 ${LAST})
	do
		if [[ ! -z ${STR} ]]; then STR="${STR} ${A[i]}"; else STR=${A[i]}; fi
	done
	echo "  Str: $STR"	# prints: "abe  carl darla ellen fanny"
}
(( 0 )) && {	# Host discovery

	# ifconfig/ping method.  May not work if hosts do not accept pings.
	#
	# BroadcastAddress=$(ifconfig eth0 |grep Bcast |awk '{print $3}' |cut -d: -f2)
	# Could replace ifconfig above: ip addr show eth0 |grep 'inet ' |grep brd |tr -s ' ' |cut -d' ' -f5
	BroadcastAddress=192.168.1.255

	# -b	allow pinging a broadcast address
	# -c	count
	# -i	interval to wait.
	ping -b -c 3 -i 20 ${BroadcastAddress}	# does NOT work on home LAN, as root or non-root.

	# nmap method.
	nmap -sP 192.168.1.1-254	# works for root.  non-root did not get all hosts.
	nmap -sP 192.168.1.*		# works for root.

	# arping method
	for N in 1 10 11 16; do arping -c 1 192.168.1.${N} |grep reply; done	# works for root.
}
(( 0 )) && {	# wireshark cli.

	# -i is capture interface
	# -k is start capture session immediately
	# -f is capture filter

	wireshark -i eth0 -k
	wireshark -i eth0 -k -f "not arp"		# filter out arp.
	wireshark -i eth0 -k -f "not tcp"		# filter out tcp.
	wireshark -i eth0 -k -f "host 192.168.1.11"	# just from baffin. CUPS, ARP, NFS, TCP, 
	wireshark -i eth0 -k -f "host 192.168.1.11 and not tcp"		# CUPS and ARP only. No TCP or NFS.
	wireshark -i eth0 -k -f "host 192.168.1.11 and arp"		# just ARP.
	wireshark -i eth0 -k -f "host 192.168.1.11 and port 631"	# just CUPS
	wireshark -i eth0 -k -f "host 192.168.1.11 and cups"			# did NOT work.
	wireshark -i eth0 -k -f "host 192.168.1.11 and arp and port 631"	# did NOT work.


	wireshark -r /full/path/to/capture-file		# eg /root/wireshark/1.cap


	# after wireshark starts, various "display" filters are possible.
	# !(udp.port == 631) and !tcp and !dns and !arp	# filters out these packets.

	# After wireshark has started, set capture filter for Ktorrent:
	# Capture > Options > filter: port 6881
	# Capture > Options > file: eg: 2011.01.31_port_6881_ver_1.cap
	# Then start the capture.  When done:
	# File > Export > Plain text: Packet summary and/or Packet details


}
(( 0 )) && {	# Use xargs to do parallel ssh.

	# put each host on it's own line. the use xargs in parrallel.
	# note "sh -c" is used to allow to build a full command line.
	echo baffin hudson pacific \
		|tr ' ' "\n" \
		|xargs -n1 -P3 -I"HOST" sh -c "ssh HOST uptime |sed -e 's;^;HOST: ;'"

	# from Leonard den Ottolander on CentOS list.
	# Backup a directory using tar, but separate tarballs for each subdir.
	# $ find <dir> -mindepth 1 -maxdepth 1 -type d -exec tar cz {} -f {}.tgz \;
	# from Nico Kadel-Garcia: You'll want quotes: "{}"
}
(( 0 )) && {	# Setting LC_COLLATE='C' permits [A-Z]* for /bin/ls or shell ls.

	# use /bin/ls.
	[ja@hudson ~]$ /bin/ls -d [A-Z]*
	bin  Desktop  etc  public  temp  verify

	# use shell ls.
	[ja@hudson ~]$ ls -d [A-Z]*
	bin  Desktop  etc  public  temp  verify

	# set LC_COLLATE='C'.  then use shell ls.
	[ja@hudson ~]$ LC_COLLATE='C' ; ls -d [A-Z]*
	Desktop

	# now use /bin/ls.
	[ja@hudson ~]$ LC_COLLATE='C' ; /bin/ls -d [A-Z]*
	Desktop
}
(( 0 )) && {	# Thanks: http://www.arrfab.net/blog/?p=246

	# The man page has an example but what I do is using ssh itself as a ProxyCommand. Just an example : suppose you need to reach HostB (not reachable from where you are) but that you can reach HostA (and that HostA can reach HostB). You can configure your ~/.ssh/config like this :

	Host HostB
	Hostname the.known.fqdn.as.resolvable.by.HostA
	User arrfab
	ForwardAgent yes
	Port 22
	ProxyCommand ssh [email protected] nc %h %p

	# And what if you need to reach HostC, which itself is only reachable by HostB ? Let’s just define a new Host section in the ~/.ssh/config and another ProxyCommand !

	Host HostC
	Hostname the.known.fqdn.as.resolvable.by.HostB
	User arrfab
	ForwardAgent yes
	Port 22
	ProxyCommand ssh remoteuser@HostB nc %h %p

	# You can now directly use the `ssh HostC` from your laptop/workstation and have a direct shell on HostC even if it has to open a connection to HostA and from there to HostB to finish to HostC.That works also for scp/sftp so you can directly copy/retrieve files to/from HostC instead of copy from one host to the next hop. More informations about those features and the correct syntax in `man ssh_config`.
}
(( 0 )) && {	# PAM.  pam authentication modules.  List frequently specified modules.

	# grep out comments and blank lines.
	# replace [...] with a placeholder
	# get the third field
	# view most frequently specified.	
	egrep -v '^#|^$' * |sed -e 's;\[.*\];placeholder;' |column -t |awk '{ print $3 }' |sort |uniq -c |sort -rn
}
(( 0 )) && {	# If you use AES, then you can use a key of length up to 32 bytes
	# Generate like:

	DDIF='if=/dev/random'	# code folding vs. kate
	dd status=noxfer $DDIF bs=16 count=1 \
		| od --width=16 -t x2 |head -1 \
		|cut -f2- -d' ' |tr -d ' ' \
		> MyKey
}
(( 0 )) && {	# Q from CentOS list: "is the areca 1100 raid controller supported by CentOS?"

	# Probably need to be root.

	# find a likely .ko file
	cd /lib/modules/2.6.18-194.8.1.el5PAE/kernel/drivers/scsi

	for F in $(find . -type f -name '*.ko'); 
	do 
		printf "%35s  %s \n"  "$F"  "$(strings $F |grep ^description |tr "\n" "\t")"

	done |grep -i areca
	# prints: ./arcmsr/arcmsr.ko  description=ARECA (ARC11xx/12xx/13xx/16xx) SATA/SAS RAID HOST Adapter 

	# cd into ./arcmsr and then get module info
	cd arcmsr
	modinfo arcmsr
}
(( 0 )) && {	# SUID and SGID. 2
	# from: http://www.standalone-sysadmin.com/blog/2010/06/setting-unix-file-permissions-numerically/
	: <<-MYCOMMENTS

	0 is nothing
	1 is sticky bit
	2 is SGID
	3 is SGID and sticky bit
	4 is SUID
	5 is SUID and sticky bit
	6 is SUID and SGID
	7 is SUID, SGID, and sticky bit 
MYCOMMENTS

	touch ttt

	echo '  Note the Upper Case "S" and "T"'
	for PERM in {0..7}
	do 
		echo -n " $PERM " ; chmod ${PERM}000 ttt \
		&& ls -l ttt | awk '{print $1}'
	done

	echo '  Note the Lower Case "s" and "t"'
	for PERM in {0..7}
	do 
		echo -n " $PERM " ; chmod ${PERM}111 ttt \
		&& ls -l ttt | awk '{print $1}'
	done

	chmod 700 ttt ; rm ttt
}
(( 0 )) && {	# SUID and SGID. 1
	# from CentOS list.  by Silviu Hutanu

	# SUID Octal perm : 4000 (chmod +s )
	# Other users execute this file as owner of file

	# GUID Octal perm: 2000  (chmod +g )
	# Other users execute this as group of the file/dir  (It can be applyied to directories )

	# Octal perm: 1000
	# Sticky bit (Ensuring that users cannot delete other users files in a directory)

	chmod u+s file		# SUID
	chmod u+g dir		# GUID
	chmod u+f file/dir	# Sticky bit
}
(( 0 )) && {	# sqlite3 play 2. From: http://souptonuts.sourceforge.net/readme_sqlite_tutorial.html

	sqlite3 test.db < trigger1
	sqlite3 test.db  "insert into t1 (data,num) values ('Number six.',8);"
	sqlite3 test.db  "select * from t1;"	# shows a date in 'timeEnter'.
}
(( 0 )) && {	# get a brief understanding of an sqlite database.

	# the yum sqlite database.
	ls /var/cache/yum/x86_64/6/updates/
	# Prints: cachecookie  e3bbabf1b23dcb92bf8dae78a86f62d8be1661b00efb809d356670534e3ee0c7-primary.sqlite  mirrorlist.txt  packages  repomd.xml

	# save the dump.
	sqlite3 e3bbabf1b23dcb92bf8dae78a86f62d8be1661b00efb809d356670534e3ee0c7-primary.sqlite ".dump" > temp.dump

	# list table sizes and col headings.
	egrep '^CREATE TABLE|INSERT INTO' temp.dump |sed -e 's;VALUES.*;;' |sort |uniq -c |sort -rn |less

	# what tables are in the db?
	sqlite3 e3bbabf1b23dcb92bf8dae78a86f62d8be1661b00efb809d356670534e3ee0c7-primary.sqlite ".table"
	# Prints: conflicts  db_info    files      obsoletes  packages   provides   requires 

	# look at column headers for the packages table.
	sqlite3 e3bbabf1b23dcb92bf8dae78a86f62d8be1661b00efb809d356670534e3ee0c7-primary.sqlite ".dump" |grep '^CREATE TABLE packages' |less

	# look at a few examples from the packages table.  Note, line insertion may include newline characters, or not.
	sqlite3 e3bbabf1b23dcb92bf8dae78a86f62d8be1661b00efb809d356670534e3ee0c7-primary.sqlite ".dump" |grep -A10 '^CREATE TABLE packages' |tail -n +2 |less

}
(( 0 )) && {	# sqlite3 play 1. From: http://souptonuts.sourceforge.net/readme_sqlite_tutorial.html

cat << 'ENDOFTRIGGER' > ~/temp/sqlite/trigger1
-- ********************************************************************
--   Creating a trigger for timeEnter
--     Run as follows:
--            $ sqlite3 test.db < trigger1
-- ********************************************************************
CREATE TRIGGER insert_t1_timeEnter AFTER  INSERT ON t1
BEGIN
 UPDATE t1 SET timeEnter = DATETIME('NOW')  WHERE rowid = new.rowid;
END;
-- ********************************************************************
ENDOFTRIGGER

}
(( 0 )) && {	# sqlite3 play 0. From: http://souptonuts.sourceforge.net/readme_sqlite_tutorial.html

	sqlite3 test.db
	sqlite3 test.db  "create table t1 (t1key INTEGER PRIMARY KEY,data TEXT,num double,timeEnter DATE);"

	sqlite3 test.db  "insert into t1 (data,num) values ('This is sample data',3);"
	sqlite3 test.db  "insert into t1 (data,num) values ('More sample data',6);"
	sqlite3 test.db  "insert into t1 (data,num) values ('And a little more',9);"
	sqlite3 test.db  "insert into t1 (data,num) values ('Here is number four',8);"
	sqlite3 test.db  "insert into t1 (data,num) values ('Here\'s number five',8);"
	sqlite3 test.db  "insert into t1 (data,num) values ('Here is number five',8);"

	sqlite3 test.db  "select * from t1 limit 2";
	sqlite3 test.db  "select * from t1";
	sqlite3 test.db  "select * from t1 offset 2";			# SQL error: near "2": syntax error
	sqlite3 test.db "select * from t1 order by t1key limit 1 offset 2";
	sqlite3 test.db "select * from t1 order by t1key offset 2";	# SQL error: near "2": syntax error

	sqlite3 test.db .dump;
	sqlite3 test.db ".dump" |sed -e s/t1/t2/|sqlite3 test2.db

}
(( 0 )) && {	# find private date in FF, after "clear private date" is run. sqlite3.

	# Setup:
	# 1.  visit www.notbig.org, or some other site, to populate FF.
	# 2.  Zoom in or out.  ## specifically for 
	# 3.  in FF, Tools -> 'Clear private data'
	# 4.  exit FF.
	# 5.  run at cli:

	cd ~ja/.moz*/fire*/*.default

	for F in ./*.{sqlite,db,mfasl} 
	do echo "===== $F"; strings $F |egrep 'notbig' ; echo -e "\n"; done |less
	# the above command identifies private data in: contents-prefs.sqlite and ybookmarks.sqlite 

	for F in ./*.{js,txt,xml,ini,dat,rdf,log,cache}
	do echo "===== $F"; egrep 'notbig' $F ; echo -e "\n"; done |less
	# the above command does NOT identify any private date in these files.

	# FYI:
	#sqlite3 ./content-prefs.sqlite .dump |less	# then search for 'notbig'.

	( echo '  Files or Dirs not looked at.  Should only be Dirs.' 
	ls -d * |egrep -v \
		'.original$|.sqlite$|.db$|.mfasl$|.js$|.txt$|.xml$|.ini$|.dat$|.rdf$|.log$|.cache$' ) \
		|less
	# the above command lists only the sub-dirs.
	# ?? what about the sub-dirs ??
	#
	# remove ./bookmarksbackups/* since it keeps url data.
}
(( 0 )) && {	# logwatch services with output.
	# run logwatch with debug level 10 to list all possible services.
	# then see which services have any output.

	CAPTURE=0
	echo '  ===== The following services have logwatch output ====='
	logwatch --service all --range 'since -7 days' --debug 10 2>/dev/null \
	|grep -v 'ReadConfigFile' \
	|while read LINE
	do
		[[ ${CAPTURE} -eq 1 ]] && echo ${LINE}
		[[ ${LINE} =~ 'Services that will be processed:' ]] && CAPTURE=1	# turn on capture.
		[[ ${LINE} =~ 'All LogFile Data:' ]] && CAPTURE=0			# turn off.

	done |egrep -v '^$|^All LogFile Data' |cut -d' ' -f3 \
	|while read S; 
	do
		OUT=$(/usr/sbin/logwatch --service ${S} --range 'since -7 days' --print)
		# [ ! -z "$OUT" ] && echo "  Service ${S} output:" && echo "===== $OUT =====" && echo && echo
		[ ! -z "$OUT" ] && echo "  ${S}"
	done

	# prints:
	: <<-MYCOMMENTS
  ===== The following services have logwatch output =====
  secure
  sudo
  sshd
  xntpd
  zz-disk_space
  zz-network
  zz-sys
  automount
  pam_unix
  yum
MYCOMMENTS

	# my choice: secure sudo sshd automount pam_unix
	# cli: logwatch --service secure --service sudo --service sshd --service automount --service pam_unix --range 'since -7 days' --print
	# Or: /usr/sbin/logwatch --service all \
	#	--service -xntpd --service -zz-disk_space --service -zz-network --service -zz-sys --service -yum \
	#	--range 'since -7 days' --print 
}
(( 0 )) && {	# aide fun. Not.

	#SINGLES=(p i n u g s b m a c acl selinux xattrs S md5 sha1 sha256 sha512 rmd160 tiger haval gost crc32 whirlpool)	# But, ignore some of the singles.

	SINGLES=(p i n u g s b m a c acl selinux xattrs S md5 sha1 sha256 sha512 rmd160 tiger)

	# groups
	R='p+i+n+u+g+s+m+c+acl+selinux+xattrs+md5'
	# ignore for now:
	#L='p+i+n+u+g+acl+selinux+xattrs'
	#E=       Empty group
	#>=       Growing logfile p+u+g+i+n+S+acl+selinux+xattrs

	# customs
	#ALLXTRAHASHES = sha1+rmd160+sha256+sha512+tiger	# ignore for now.
	#EVERYTHING = R+ALLXTRAHASHES				# ignore for now.
	#NORMAL = R+rmd160+sha256
	#DIR = p+i+n+u+g+acl+selinux+xattrs
	#PERMS = p+i+u+g+acl+selinux
	#LOG = >						# ignore for now.
	#LSPP = R+sha256
	#DATAONLY =  p+n+u+g+s+acl+selinux+xattrs+md5+sha256+rmd160+tiger

	CONF='/etc/aide.conf.original'
	grep ^[A-Z] ${CONF} |egrep -v '^ALLXTRAHASHES|^EVERYTHING|^LOG' \
	|while read LINE
	do
		KEY=$(echo "${LINE}" |sed -e 's; *= *.*$;;')
		VAL=$(echo "${LINE}" |sed -e 's;^.*= *;;')
		echo "  Line: ${LINE}"
		echo "   Key: ${KEY}"
		echo "   Val: ${VAL}"

		#VAL=$(echo "${VAL}" |sed -e 's;R;$R\+;')
		#VAL=$(eval ${VAL})

		VAL=$(echo "${VAL}" |sed -e 's;R;YouShitFace+;')
		echo "   Val: ${VAL}"
		echo
	done
}
(( 0 )) && {	# One-liners

	man 7 ascii		# ascii table

	ssh -t reachable_host ssh unreachable_host
	# This one-liner creates an ssh connection to unreachable_host via reachable_host.
	# -t allocates a pseudo-tty, necessary for working interactively in the second ssh
}
(( 0 )) && {	# Minimum example of how ssh ControlMaster interfeers with my fsck script.
	# 

	for HOST in baffin hudson pacific
	do
		for PART in /dev/sda1 /dev/mapper/VolGroup00-LogVol00
		do
			ssh -tt ${HOST} "sudo /sbin/tune2fs -l ${PART}" \
			> /tmp/min.fsck.${HOST}.$(basename ${PART}) &
		done
	done
	wait
	ls -l /tmp/min.fsck.*

}
(( 0 )) && {	# Get the PID and Return Status of background processes.

	# start bg processes and collect PIDs
	ls /bin/k* &
	PIDA=$!
	du -sh /bin &
	PIDB=$!
	ls /bumperonni &
	PIDC=$!

	# wait for each PID to finish, then print return code.
	wait $PIDA
	RCA=$? ; echo "  Return Code A: $RCA"
	wait $PIDB
	RCB=$? ; echo "  Return Code B: $RCB"
	wait $PIDC
	RCC=$? ; echo "  Return Code C: $RCC"
}
(( 0 )) && {	# Find the unique words in a text file.

	cd ~/temp/

	grep -v ^match nmap-service-probes > a

	while read L
	do
		M=$(echo "$L" |tr ' ' "\n")
		echo "$M"
	done < a >b

	cat b |sort -u |grep ^[a-zA-Z] |grep -v ^http > c

	cat c |tr 'A-Z' 'a-z' |sort -u > d
}
(( 0 )) && {	# See which hosts are available, then use just those.

	for HOST in $HOSTS
	do
		if ! ping -W 1 -c 1 $HOST &>/dev/null
		then
			echo "  Host not available: $HOST" && continue
		fi
		HOSTS_AVAIL="${HOSTS_AVAIL} $HOST"
	done
	echo "  Hosts available: ${HOSTS_AVAIL}"
}
(( 0 )) && {	# System Info

	/usr/sbin/dmidecode
	/usr/sbin/biosdecode
}
(( 0 )) && {	# Something works OR (echo error message && exit 1)

	TEMPFILE=$(mktemp /home/ja/some.name.XXXXXXXXXX) \
		|| ( echo "this is an error message" && exit 1 )
	# creates file, as expected.

	TEMPFILE=$(mktemp /root/some.name.XXXXXXXXXX) \
		|| ( echo "this is an error message.  error code: $?" && exit 49000 )
	# does NOT create file, as expected.  displayes $? as 1.
	# at cli, "echo $?" => 1
	# Why did it not display 49000 ???

	TEMPFILE=$(mktemp /root/some.name.XXXXXXXXXX) \
	[ ! -f ${TEMPFILE} ] && echo "this is another error message.  Error code: $?" && exit 49001
	# does NOT display the echo.
	# $? is 1.
}
(( 0 )) && {	# one-liners from: http://www.catonmat.net/blog

	$ > file.txt	# either empties file.txt or creates a new file.txt.
}
(( 0 )) && {	# get wireless access point info.  there is some duplication.  See also: iwconfig.
	# runs on netbook, but not desktop.

	for ARG in scan freq chan rate key power txpower retry peers event auth wpakeys genie modulation
	do
		echo -e "\n$ARG\n"
		sudo iwlist ra0 $ARG
	done
}
(( 0 )) && {	# Compare an app output over time.  version 1
	# something may be lost between diffs.

	LOG=/tmp/log_of_netstat_pltn
	SLEEP=3	# seconds.

	(
	echo "  ===== Netstat -pltn, as of $(date +"%F--%T")"
	netstat -pltn
	echo
	sleep $SLEEP

	for X in {1..3}
	do
		echo "  ===== Netstat -pltn DIFF, as of $(date +"%F--%T")"
		diff <(netstat -pltn) <(sleep $SLEEP; netstat -pltn)
		echo
	done
	) > $LOG
	echo "  Kindly check logfile at $LOG"
}
(( 0 )) && {	# Compare an app output over 10 seconds.

	diff <(netstat -pltn) <(sleep 10; netstat -pltn)
}
(( 0 )) && {	# Compare an apps open files over 10 seconds.

	LSOF=/usr/sbin/lsof
	PID=2238
	diff <($LSOF -p $PID) <(sleep 10; $LSOF -p $PID)
}
(( 0 )) && {	# display a process tree.  May be convenient for finding multiple processes for same app.

	# u=show uid transitions
	# p=show PIDs
	pstree -up
}
(( 0 )) && {	# VGA Resolution Codes for GRUB and Lilo.  Add to grub boot line.

	: <<-MYCOMMENTS

--- Depth --
Colors  bits  640x480  800×600  1024×768  1152×864 1280×1024  1600×1200
   256    8   vga=769  vga=771   vga=773   vga=353   vga=775    vga=796
 32000    ?   vga=784  vga=787   vga=790   vga= ?    vga=793    vga= ? 
 65000   16   vga=785  vga=788   vga=791   vga=355   vga=794    vga=798
 16.7M   24   vga=786  vga=789   vga=792   ?         vga=795    vga=799

	MYCOMMENTS
}
(( 0 )) && {	# find the longest words without using some letters.
	# without using any letters with tails or stalks?".
	# from: http://www.openfusion.net/linux/the_joy_of_scripting

	echo COULD NOT DUPLICATE

	#egrep -v '[A-Zbdfghjklpqty]' /usr/share/dict/words | \
	#perl -nle 'chomp; push @words, $_; 
	#  END { @words = sort { length($b) cmp length($a) } @words; 
	#	print join "\n", @words[0 .. 9] }' 

	# Prints:
	# noncarnivorousness
	# nonceremoniousness
	# overcensoriousness
	# carnivorousnesses
	# noncensoriousness
	# nonsuccessiveness
	# overconsciousness
	# semiconsciousness
	# unacrimoniousness
	# uncarnivorousness
}
(( 0 )) && {	# Get an english word list from <file>

	#cat <file> | tr -sc A-Za-z '\012'	# '\012' is a newline.
	# -s = squeeze
	# -c = compliment
	# So, tr -c A-Za-z will replace all non-letters with '\012'
	# Then '\012' will be squeezed.
	#
	# Could replace '\012' with "\n"
	cat vim_notes | tr -sc A-Za-z "\n"
}
(( 0 )) && {	# Indirect variable expansion in bash.

	test.function()
	{
		if [ -n "$1" ]
		then echo "value of [${1}] is: [${!1}]"
		else echo "Null parameter passed to this function"
		fi
	}
	Variable="My.Darling.String"
	test.function Variable
	#prints:	value of [Variable] is: [My.Darling.String]

	# If the first character of parameter is an "!", a level of variable indirection is introduced. 
	# Bash uses the value of the variable formed from the rest of parameter as the name of the variable; this variable is then expanded and that value is used in the rest of the substitution, rather than the value of parameter itself. This is known as indirect expansion. 
}
(( 0 )) && {	# run a program at 2:35 at the first Saturday of each odd month.

	# from: [email protected] on CentOS list.
	35 2 1-7 1,3,5,7,9,11 * [ "$(date '+\%a')" == "Sat" ] && some.command

	# Or, for readability:
	35 2 1-7 Jan,Mar,May,Jul,Sep,Nov * [ "$(date '+\%a')" == "Sat" ] && some.command
}
(( 0 )) && {	# cron job to run every other week on Saturday (NOT first and third week ). 1.
	# from CentOS list, Jan 6, 2010: John R Pierce

	# [ $(( ($(date +"%s") / 86400) % 14)) -eq 9 ]
	# where  %s is seconds since 1970-01-01 00:00:00 UTC, which was a Wednesday here (PST).
	# ja notes:
	#	- modulo 14 yields 0..13
	#	- Running the code below on a Wednesday yields a modulo of 13.  IE: wed=13
	#	- So, backing up to Saturday means a modulo of 9

	echo "  $(date)"
	SecSinceEpoch=$(date +"%s")
	DaysSinceEpoch=$(( $SecSinceEpoch / 86400 ))
	DaysMod14=$(( $DaysSinceEpoch % 14 ))

	printf "  SSE: %-15s DSE: %-8s DM14: %-4s \n" "$SecSinceEpoch" "$DaysSinceEpoch" "$DaysMod14"
	echo

	# ja note: both poposed solutions seem to ignore months, just doing every other Sat thru/out the year.
}
(( 0 )) && {	# cron job to run every other week on Saturday (NOT first and third week ). 0.
	# from CentOS list, Jan 6, 2010.

	for D in {1..31}; do echo $(($D%14)); done	# prints 1..13, 0..13, 0..3

	# date yields digits for day of the month.  eg: 06 for Jan 6.
	# So, this seems to work: 0 0 * * 6	[ $((`date +"%d"`%14)) -ge 8 ] && script.sh
}
(( 0 )) && {	# play with "command blocks" and failure.

	# this works.
	#cd wxyz || { echo "  The cd command failed" ; exit 1
	#}

	# this fails.
	#cd wxyz || { echo "  The cd command failed" ; exit 1 }

	# this only exits the sub-shell.
	cd wxyz || ( echo "  The cd command failed" ; exit 1 )

	# Darn.  I guess I'll have to skip the echo part. Like in man mktemp

	echo "  This line is printed if the above command does not exit."

	#TEMPDIR=$(mktemp -d /tmp/t.XXXXXXXXXX)

}
(( 0 )) && {	# given a table of values, space filled, see if all values in a line are equal.
	# NB: all 3 ways yield the same result.  The last is more versetile.

	F=/tmp/TTTT.$$
cat << _BOINK_ > $F
       1       1       1       1
       2       1       1       1
       1       2       1       1
       1       1       2       1
       1       1       1       2
_BOINK_

	declare -a HITS
	while read LINE
	do
		HITS=($LINE)
		for i in "${HITS[@]}"; do echo $i; done

		COUNT=${#HITS[@]}	# prints: 4
		echo "  Number of elements in array HITS: $COUNT"
		[ ${HITS[0]} -ne ${HITS[1]} ] && echo NotTheSame01
		[ ${HITS[1]} -ne ${HITS[2]} ] && echo NotTheSame12
		[ ${HITS[2]} -ne ${HITS[3]} ] && echo NotTheSame23

		for i in 0 1 2
		do
			j=$((i + 1))
			[ ${HITS[$i]} -ne ${HITS[$j]} ] && echo NotTheSame$i$j
		done

		UPPER=$((COUNT-2)) ; echo "  Upper: $UPPER"
		for i in $(seq 0 $UPPER)
		do
			j=$((i + 1))
			[ ${HITS[$i]} -ne ${HITS[$j]} ] && echo NotTheSame$i$j
		done

		echo
	done < $F
}
(( 0 )) && {	# compare chkconfig, ps, ... Probably not too helpful.
	# Maybe compare processes across hosts.  See ~ja/bin/table_processes_all_hosts
	# Maybe see where each process comes from. ie, user started, init started, kernel thread, ...

	TEMPDIR=$(mktemp -d /tmp/compare.chkconfig.ps.XXXXXXXXXX)

	# list services that are "on" for some runlevels.
	/sbin/chkconfig --list |grep ':on' |awk '{print $1}' > ${TEMPDIR}/services

	# Some processes have a trailing colon ":". Remove it.
	ps -eo cmd |egrep -v '^CMD|^\[' |awk '{print $1}' |sed -e 's;\:$;;' > ${TEMPDIR}/ps1

	# groom the list of processes.  ie: basename and unique.
	while read NAME
	do
		echo "$(/bin/basename -- "$NAME")"
	done < ${TEMPDIR}/ps1 |sort -u > ${TEMPDIR}/ps2

	# which services are processes?
	while read S
	do
		while read P
		do
			if [ "$P" == "$S" ]
			then printf "  S: %-20s P: %-20s \n" "$S" "$P" >> ${TEMPDIR}/match

			elif echo "$P" |grep -q "$S"
			then 
				printf "  S: %-20s P: %-20s \n" "$S" "$P" \
				>> ${TEMPDIR}/match.some1
				# This is a partial match. eg: cups/cupsd
				# or cups/eggcups or syslog/syslogd.
				# So, test for a trailing 'd' and report.
				[ "${P}" == "${S}d" ] \
				&& printf "  S: %-20s P: %-20s \n" "$S" "$P" \
				>> ${TEMPDIR}/match

			else printf "  S: %-20s P: %-20s \n" "$S" "$P" >> ${TEMPDIR}/match.no
			fi
		done < ${TEMPDIR}/ps2
	done < ${TEMPDIR}/services
	chown -R ja:ja ${TEMPDIR}
	exit 0
}
(( 0 )) && {	# Using tmpfs. (ramdisk)
	# Thanks: http://kevin.vanzonneveld.net/techblog/article/create_turbocharged_storage_using_tmpfs/

	# copy a file to ramdisk.
	cp -af /root/100mb.bin /dev/shm/	# Now it's in your RAM!

	# Maybe the limit of half of your physical RAM is not sufficient.
	mount -o remount,size=4G /dev/shm

	# Create a new volume
	# Create a tmpfs instance on /var/www/www.mysite.com/ramdrive with a max of 500MB RAM,
	# that can only be changed by root, but accessed by everyone (like Apache):
	mkdir -p /var/www/www.mysite.com/ramdrive
	mount -t tmpfs -o size=500M,mode=0744 tmpfs /var/www/www.mysite.com/ramdrive

	# Add the following line to your /etc/fstab:
	tmpfs /var/www/www.mysite.com/ramdrive tmpfs size=500M,mode=0777 0 0
	# change mode 0777 to a suitable umask.

	# ja note: maybe for temp files or temp dirs:
	TEMPDIR=$(mktemp -d /dev/shm/script.name.XXXXXXXXXX)
}
(( 0 )) && {	# convert a street address to lat/lon
	# thanks: http://www.linuxjournal.com/article/10589 (whereis.sh)

	URL='http://api.maps.yahoo.com/ajax/geocode'
	ARGS='?appid=onestep&qt=1&id=m&qs='
	ADDR="$(echo $* | sed 's/ /+/g')"
	curl -s "${URL}${ARGS}${ADDR}" | cut -d\" -f13,15 | sed 's/[^0-9\.\,\-]//g;s/,$//'
}
(( 0 )) && {	# convert a street address to lat/lon.  Thanks: linuxjournal.com

	URL='http://api.maps.yahoo.com/ajax/geocode'
	ARGS='?appid=onestep&qt=1&id=m&qs='
	ADDR="$(echo $* | sed 's/ /+/g')"
	curl -s "${URL}${ARGS}${ADDR}" | cut -d\" -f13,15 | sed 's/[^0-9\.\,\-]//g;s/,$//'

	# Take the lat/lon above from the standard input. 
	# Convert to Degrees/Minutes format and figure out whether it is a N/S lat and E/W lon. 
	# Then loops through the JPEGg images in the current directory and sets the lat/lon, using exiv2

	##### NOT TESTED.

	IFS=","
	read lat long

	# If sign is negative, we have to change reference
	latRef="N";
	latSign=$(echo $lat | cut -c 1)
	if [ "X$latSign" = "X-" ]
	then  # Delete minus from beginning
	  lat=$(echo $lat | sed s/^-//)
	  latRef="S"
	fi
	lonRef="E";
	lonSign=$(echo $long | cut -c 1)
	if [ "X$lonSign" = "X-" ]
	then
	  long=$(echo $long | sed s/^-//)
	  lonRef="W"
	fi

	# Calculate lat/lon degrees and minutes
	latDeg=$( echo "scale=0; $lat/1" | bc )
	latMin=$( echo "scale=2; m=($lat-$latDeg) *100/ 0.016666;scale=0;m/1" | bc ) 
	lonDeg=$( echo "scale=0; $long/1" | bc )
	lonMin=$( echo "scale=2; m=($long-$lonDeg)*100/0.016666;scale=0;m/1" | bc )

	echo Picture location will be: $latDeg $latMin\' $latRef , $lonDeg $lonMin\' $lonRef

	for fil in *.jpg  # Also try *.JPG
	do
	  echo Updating $fil ....
	  exiv2 -M"set Exif.GPSInfo.GPSLatitude $latDeg/1 $latMin/100 0/1" \
		-M"set Exif.GPSInfo.GPSLatitudeRef $latRef" \
	        -M"set Exif.GPSInfo.GPSLongitude $lonDeg/1 $lonMin/100 0/1" \
		-M"set Exif.GPSInfo.GPSLongitudeRef $lonRef" \
		$fil
	done
}
(( 0 )) && {	# symbolic links and 'readlink -f'

	D=/home/ja/temp/t-readlink
	mkdir -p $D
	cd $D

	# link to a dir on host's /tmp
	[ ! -L tmp1 ] && ln -s /tmp ./tmp1	# if tmp1 does not exist, or is not a symlink, create it.
	ls -l tmp1
	# prints: lrwxrwxrwx 1 ja ja 4 Nov 30 09:36 tmp1 -> /tmp
	readlink -f tmp1
	# prints: /tmp

	# link to another file within the mount point.
	[ ! -L tmp2 ] && ln -s ../vim_notes ./tmp2
	ls -l tmp2
	# prints: lrwxrwxrwx 1 ja ja 12 Nov 30 09:46 tmp2 -> ../vim_notes
	readlink -f tmp2
	# prints: /mnt/fundy/ja/temp/vim_notes

	# link to a non-existant file within the mount point.
	[ ! -L tmp3 ] && ln -s ../i-am-not-here ./tmp3
	ls -l tmp3
	# prints: lrwxrwxrwx 1 ja ja 16 Nov 30 09:50 tmp3 -> ../i-am-not-here
	readlink -f tmp3
	# prints: /mnt/fundy/ja/temp/i-am-not-here

	# So, we can link to a file or dir, existing or not, on the host or on a mount point.
	# In each case, 'readlink' reports the correct "real path".

	# link to a file through a non-existing dir.
	[ ! -L tmp4 ] && ln -s ../i-am-not-here/me-too ./tmp4
	ls -l tmp4
	# prints: lrwxrwxrwx 1 ja ja 23 Nov 30 09:55 tmp4 -> ../i-am-not-here/me-too
	readlink -f tmp4
	# NO output.

	# NB: the links to non-existent dirs or files are shown in red within a terminal listing.

}
(( 0 )) && {	# version 1 of  *parsing* an RPM filename into NAME, VER, REL, FROM, ARCH
	# elsewhere we see which RPMS to update.

	#DIR=/share/CentOS/5.4/os/i386/CentOS
	DIR=/share/CentOS/5.4/updates/i386/RPMS
	cd ${DIR} || exit 1
	ls |sed -e 's;\.rpm$;;' |while read R
	do
		# Parse recent additions to the *local* updates repo.
		ARCH=''; REST=''; FROM=''; RES2=''; REL=''; RES3=''; VER=''; NAME=''

		ARCH=".${R##*.}" ; REST=${R%.*}

		if echo $REST |grep -q '\.el5'
		then 
			FROM=$(echo $REST |sed -e 's;.*\.el5;.el5;')
			RES2=${R%.el5*}

		elif echo $REST |grep -q '\.fc6'
		then
			FROM=$(echo $REST |sed -e 's;.*\.fc6;.fc6;')
			RES2=${R%.fc6*}

		else	RES2=$REST
		fi

		REL="-${RES2##*-}" ; RES3=${RES2%-*}
		VER="-${RES3##*-}" ; NAME=${RES3%-*}

		printf "  %-65s %-50s %-15s %-20s %-20s %-12s \n" \
			"$R" "$NAME" "$VER" "$REL" "$FROM" "$ARCH"
	done
}
(( 0 )) && {	# version 0 of parsing an RPM filename into NAME, VER, REL, FROM, ARCH

	# grep ^RPMS ~ja/bin/support/logs/repo.updates* \
	#DIR=/share/CentOS/5.4/updates/i386/RPMS
	DIR=/share/CentOS/5.4/os/i386/CentOS

	[ ! -d ${DIR} ] && echo "  Not a dir: ${DIR}" && exit 1

	ls -l ${DIR}/* \
		|sed -e 's;^.*RPMS/;;' -e 's;^.*i386/CentOS/;;' -e 's;\.rpm$;;' \
		|while read R
		do
			# Parse recent additions to the *local* updates repo.
			ARCH=''; REST=''; FROM=''; RES2=''; REL=''; RES3=''; VER=''; NAME=''
			ARCH=".${R##*.}"
			REST=${R%.*}

			if echo $REST |grep -q '\.el5'
			then 
				FROM=$(echo $REST |sed -e 's;.*\.el5;.el5;')
				RES2=${R%.el5*}

			elif echo $REST |grep -q '\.fc6'
			then
				FROM=$(echo $REST |sed -e 's;.*\.fc6;.fc6;')
				RES2=${R%.fc6*}

			else	RES2=$REST
			fi

			REL="-${RES2##*-}"
			RES3=${RES2%-*}
			VER="-${RES3##*-}"
			NAME=${RES3%-*}

			printf "  %-65s %-50s %-15s %-20s %-20s %-12s \n" \
			         "$R" "$NAME" "$VER" "$REL" "$FROM" "$ARCH"
continue
			# Compare recent additions to current rpm database.
			OUT=$(rpm -q $NAME)	# output
			echo "     RPM: $R"
			echo "    Name: $NAME"
			echo "     Out: $OUT"

			# if already installed, do nothing.
			[ "$OUT" == "$R" ] && echo && continue

			# if not installed, do nothing.
			[[ "$OUT" =~ "is not installed" ]] && echo && continue

			# if installed but different from $R, then update 
			[ "$OUT" != "$R" ] && echo "    Kindly update $NAME"
			echo
		done
}
(( 0 )) && {	# ? Change file associations.

	echo /usr/share/applications/defaults.list
}
(( 0 )) && {	# Look for duplicates in trees.

	# SIZER=' -size +10240k'	# look at all files GT 10240K
	SIZER=' -size +0'		# look at all files GT 0
	# SIZER=""			# do not consider size

	# DIRS=". "			# look in current dir.
	DIRS='/home/ja/temp/downloads/perl/Template-Toolkit-2.15/ /home/ja/temp/RPM/'

	# --check-chars=32 will only look at the first 32 characters.
	# --all-repeated=prepend

	find $DIRS -type f $SIZER -print0 |xargs -0 md5sum |sort \
		|uniq --check-chars=32 --all-repeated=prepend
}
(( 0 )) && {	# Test parts of /usr/bin/ldd

    printf "Copyright (C) %s Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
" "2006"
    printf "Written by %s and %s.
" "Roland McGrath" "Ulrich Drepper"

echo

    printf $"Copyright (C) %s Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
" "2006"
    printf $"Written by %s and %s.
" "Roland McGrath" "Ulrich Drepper"

# NO difference in output.
# 2 minor differences: 1) leading $ is not needed.  2) use of a real newline vs. use of \n.

}
(( 0 )) && {	# Immutable files

	# Even root cannot delete the files.

	chattr +i test_file	# set immutable flag.
	chattr -i test_file	# unset
	lsattr test_file	# see attr properties
	# prints: ----i--------  test_file
}
(( 0 )) && {	# mtr = "My TraceRoute"

	# must be root to run
	# i=interval in seconds between ICMP ECHO requests
	# /usr/sbin/mtr -i5 74.208.24.115
	/usr/sbin/mtr -i5 www.notbig.org
}
(( 0 )) && {	# See when or who changes a file.
	# Thanks: http://kbase.redhat.com/faq/docs/DOC-10108

	# make sure auditd is running.
	/sbin/chkconfig --list |grep -i 'audit'
	service auditd start

	# test file.
	touch /root/audit-test

	# add a "watch"
	# -w=watch-file.  -p=permissions-to-check.  -k=key-name(for easy access, 31 bytes max)
	auditctl -w /root/audit-test -p a -k hosts-file

	# change the test file.
	touch /root/audit-test 

	# see what audit search says
	# -ts=time-start(when to start searching)
	ausearch -ts today -k hosts-file
# ----
# time->Fri Oct  9 08:19:16 2009
# type=CONFIG_CHANGE msg=audit(1255101556.462:4): auid=4294967295 op=remove rule key="hosts-file" list=4 res=1
# ----
# time->Fri Oct  9 08:19:41 2009
# type=CONFIG_CHANGE msg=audit(1255101581.281:6): auid=4294967295 op=add rule key="hosts-file" list=4 res=1

	auditctl -W /root/audit-test
	# got error msg: 
	#   Error sending delete rule data request (No such file or directory)
	# ???

	service auditd stop
}
(( 0 )) && {	# Peru: expand highlight filename to include full dirname.

	for F in /data/oat_2009/stills-03/highlights-peru/*.jpg
	do
		DN=$(dirname $F)
		BN=$(basename $F)
		# printf "  %-60s %-60s %-10s \n" "$F" "$DN" "$BN"

		FN=$(find /data/oat_2009/stills-03/peru -iname "*$BN" -type f)
		DN2=$(dirname $FN)
		DN3=$(echo $DN2 |sed -e 's;^.*stills-03/;;' -e 's;/;-;g')
		# printf "  %-60s %-60s %-60s \n" "$FN" "$DN2" "$DN3"

		NEWFN="$DN/$DN3-$BN"
		# echo "  $NEWFN"
		echo "  Moving from: $F"
		echo "           to: $NEWFN"
		echo
		mv "$F" "$NEWFN"
	done

}
(( 0 )) && {	# Ecuador: expand highlight filename to include full dirname.

	for F in /data/oat_2009/stills-03/highlights-ecuador/*.jpg
	do
		DN=$(dirname $F)
		BN=$(basename $F)
		# printf "  %-60s %-60s %-10s \n" "$F" "$DN" "$BN"

		FN=$(find /data/oat_2009/stills-03/ecuador -iname "*$BN" -type f)
		DN2=$(dirname $FN)
		DN3=$(echo $DN2 |sed -e 's;^.*stills-03/;;' -e 's;/;-;g')
		# printf "  %-60s %-60s %-60s \n" "$FN" "$DN2" "$DN3"

		NEWFN="$DN/$DN3-$BN"
		# echo "  $NEWFN"
		echo "  Moving from: $F"
		echo "           to: $NEWFN"
		echo
		mv "$F" "$NEWFN"
	done

}
(( 0 )) && {	# convert filenames from digitdigit-text to letter-text
	# eg: 01-blah to a-blah, 02-blah to b-blah, ..., thru 26-blah to z-blah.
	# Plan: convert 01 to 1 to a.  IE: remove leading zero, then access an array.

	CHARS=([1]=a b c d e f g h i j k l m n o p q r s t u v w x y z)
	TEMPDIR=$(mktemp -d /tmp/filename-convert-test.XXXXXXXXXX)

	# Create filenames for testing.
	for C in $(seq --format=%02.f 1 21)
	do
		touch "${TEMPDIR}/${C}-blah"
	done

	# List before and after filenames.
	for F in ${TEMPDIR}/*
	do
		DN=$(dirname $F)			# get dirname
		BN=$(basename $F)			# get basename
		TWO=$(echo $BN |cut -b1-2)		# get first 2 characters of basename
		TWO2=${TWO#0}				# remove leading zero, if exists.
		REST=$(echo $BN |cut -b3-)		# get third and remaining characters of basename.
		NEW="${DN}/${CHARS[$TWO2]}${REST}"
		printf "  %-50s %2s %2s %2s %50s \n" "$F" "$TWO" "$TWO2" "${CHARS[$TWO2]}" "$NEW"

	done

	rm ${TEMPDIR}/*
	rmdir ${TEMPDIR}

	# ToDo
	# test for other filenames in dir.
	# test for LT 27 filenames.
	# test for first two being digits.
	# ?
}
(( 0 )) && {	# Fetch the front page from Google

	exec 3<>/dev/tcp/www.google.com/80
	echo -e "GET / HTTP/1.1\r\nhost: http://www.google.com\r\nConnection: close\r\n\r\n" >&3
	cat <&3

	# The first line causes file descriptor 3 to be opened 
	# for reading and writing on the specified TCP/IP socket. 
	#
	# This is a special form of the exec statement. From the bash man page:
	#	exec [-cl] [-a name] [command [arguments]]
	# ... If command is not specified, 
	# any redirections take effect in the current shell, 
	# and the return status is 0.

	# In third line, we read the response out of the socket using cat <&3, 
	# which reads the response and prints it out. 
	# The response being the main HTML page from Google.
}
(( 0 )) && {	# Using here documments for tests in sed or grep
	# In these examples, first) grep non-empty lines and second) del empty lines.

cat <<-EOF | grep .
linha com algo


outra lnha com algo
EOF

# apagando linhas em branco com o sed
cat <<-EOF | sed '/^$/d'
asdfa


asdfa
EOF
}
(( 0 )) && {	# Date. Test for last day of the month.
	# Might be useful in cronjobs.

	[ $(date --date='next day' +'%B') == $(date +'%B') ] \
		|| echo 'Today is the last day of this month.'
}
(( 0 )) && {	# bash test suite example
	# From: http://code.google.com/p/shunit2/wiki/HOWTO_TestAbsolutePathFn

shlib_relToAbsPath()
{
  shlib_path_=$1

  # prepend current directory to relative paths
  echo "${shlib_path_}" |grep '^/' >/dev/null 2>&1 \
      || shlib_path_="`pwd`/${shlib_path_}"

  # clean up the path. if all seds supported true regular expressions, then
  # this is what it would be:
  shlib_old_=${shlib_path_}
  while true; do
    shlib_new_=`echo "${shlib_old_}" |sed 's/[^/]*\/\.\.\/*//g;s/\/\.\//\//'`
    [ "${shlib_old_}" = "${shlib_new_}" ] && break
    shlib_old_=${shlib_new_}
  done
  echo "${shlib_new_}"

  unset shlib_path_ shlib_old_ shlib_new_
}

testRelToAbsPath()
{
  parent=`dirname ${PWD}`

  # save stdin and redirect it from an in-line file
  exec 9<&0 <<EOF
abc                    ${PWD}/abc
abc/def                ${PWD}/abc/def
abc/def/ghi            ${PWD}/abc/def/ghi
abc/./def              ${PWD}/abc/def
abc/../def             ${PWD}/def
abc/../def/../ghi      ${PWD}/ghi
/abc                   /abc
/abc/def               /abc/def
/abc/def/ghi           /abc/def/ghi
/abc/def/../../ghi     /ghi
/abc/def/ghi/../../jkl /abc/jkl
/abc/../def            /def
/abc/../def/../ghi     /ghi
./abc                  ${PWD}/abc
../abc                 ${parent}/abc
../abc/def             ${parent}/abc/def
EOF
  while read relPath absPath; do
	# ja test
	# echo "  relPath: $relPath  absPath: $absPath"
	# printf "  relPath: %-25s %s \n" "$relPath" "$absPath"
	# continue

    # ignore comment and blank lines
    echo "${relPath}" |egrep -v "^(#|$)" >/dev/null || continue

    # test the function
    newPath=`shlib_relToAbsPath "${relPath}"`
    # assertEquals "${relPath}" "${absPath}" "${newPath}"
    printf "  %-35s %-35s %s \n" "${relPath}" "${absPath}" "${newPath}"
  done
  exec 0<&9 9<&-
}

testRelToAbsPath

}
(( 0 )) && {	# get sdparms from attached portable hdd used for backups

	DIR=/media/disk

	# How many portable hdd devices are attached?
	COUNT=$(mount |grep -c "${DIR}")
	[ $COUNT -ne 1 ] \
		&& echo "  There are $COUNT attached portable hdd devices.  Kindly investigate. Exiting!" \
		&& exit 1

	# Only 1 is attached.  Verify it holds a copy of the backups.
	[ ! -d "${DIR}/backups/ja" ] \
		&& echo '  Dir not found: ${DIR}/backups/ja' \
		&& exit 1

	# Get drive name, eg: /dev/sdb; not partition name, eg: /dev/sdb1.
	NAME=$(mount |grep "${DIR}" |cut -d' ' -f1 |sed -e 's;[0-9]*$;;')

	# Print timestamp, mount options, and sdparms.
	echo "    =========== Mount options and sdparms for attached portable usb hdd used for backups."
	echo "    =========== $(date)"
	echo
	echo "    $(mount |grep "${DIR}")"
	echo
	/usr/bin/sdparm --all --long --long ${NAME}
	echo
}
(( 0 )) && {	# Read or Change portable HDD parms with sdparms

	/usr/bin/sdparm -a		# read all
	/usr/bin/sdparm --all --long --long /dev/sdb

	/usr/bin/sdparm --enumerate --all --long --long /dev/sdb

	/usr/bin/sdparm --get=STANDBY /dev/sdb
	/usr/bin/sdparm --get=STANDBY=1 /dev/sdb
	/usr/bin/sdparm --get=STANDBY --long /dev/sdb
	/usr/bin/sdparm --get=STANDBY --long --long /dev/sdb

	/usr/bin/sdparm --command=capacity /dev/sdb

	/usr/bin/sdparm --inquiry /dev/sdb
	/usr/bin/sdparm --inquiry /dev/sdb

	/usr/bin/sdparm --page=po /dev/sdb
}
(( 0 )) && {	# Notes on changing Seagate hdd parms.

### After some period of time, the Seagate FreeAgent Go portable hdd goes read-only.
### 3000 of the 100ms.  => 300s, => 5m
### Messing with the Seagate hdd parms is not enough to easily go from ro to rw on an ad-hoc basis.

### time passes, ...

### The process of unmount, then mount, then maybe some hdd parm commands,
###	is more trouble than it is worth.  Simpler to use mouse to right-click unmount,
###	then physically remove usb plug, then re-insert usb plug and let the system automount it.
###
## But,	it might just be easier to turn off the Seagate hdd parm for energy saving.
##	That is: turn of "STANDBY" timer.

### time passes, ...

(plug-in usb portable hdd)

[root@fundy ~]# date ; touch /media/disk/Sync/test-rw-mount ; ll /media/disk/Sync/test-rw-mount 
Mon Sep 28 13:05:23 PDT 2009
-rw-r--r-- 1 root root 0 Sep 28 13:05 /media/disk/Sync/test-rw-mount

[root@fundy ~]# /usr/bin/sdparm --command=start /dev/sdb; EC=$?; echo "  Error Code: $EC"
    /dev/sdb: Seagate   FreeAgent Go     102D
  Error Code: 0
[root@fundy ~]# /usr/bin/sdparm --clear STANDBY -6 /dev/sdb; EC=$?; echo "  Error Code: $EC"
    /dev/sdb: Seagate   FreeAgent Go     102D
  Error Code: 0
[root@fundy ~]# /usr/bin/sdparm -a /dev/sdb; EC=$?; echo "  Error Code: $EC"
    /dev/sdb: Seagate   FreeAgent Go     102D
Power condition mode page:
  IDLE        0  [cha: n, def:  0, sav:  0]
  STANDBY     0  [cha: n, def:  1, sav:  0]
  ICT         0  [cha: n, def:  0, sav:  0]
  SCT         0  [cha: n, def:3000, sav:  0]
  Error Code: 0
[root@fundy ~]# date ; touch /media/disk/Sync/test-rw-mount ; ll /media/disk/Sync/test-rw-mount 
Mon Sep 28 13:09:32 PDT 2009
-rw-r--r-- 1 root root 0 Sep 28 13:09 /media/disk/Sync/test-rw-mount
}
(( 0 )) && {	# bashrc for multi-user accounts from remote host.

	TTY=`ps |head -n 2|tail -n 1|awk '{print $2}'`
	# eg: 3534 pts/5  and-so-on

	RIP=`w|grep $TTY|awk '{print $3}'`	# remote IP or FQDN, eg fundy.brc.localn
	# eg: ja pts/5 fundy.brc.localn and-so-on
	# yields: fundy.brc.localn
	# NB: the "FROM" column is truncated.  Better not match on full name.

	case $RIP in
	        10.0.100.162 )	export EDITOR=joe	;;
	        * )		export EDITOR=nano	;;
	esac
}
(( 0 )) && {	# Text to wave or spoken.
	echo "Four score and seven years ago" | /usr/bin/text2wave | aplay 2>/dev/null
}
(( 0 )) && {	# Random password generator by Antek Sawicki <[email protected]>,
# From: http://snipt.net/voyeg3r/script-para-gerar-senhas

MATRIX="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
# ==> Password will consist of alphanumeric characters.
LENGTH="8"
# ==> May change 'LENGTH' for longer password.


while [ "${n:=1}" -le "$LENGTH" ]
# ==> Recall that := is "default substitution" operator.
# ==> So, if 'n' has not been initialized, set it to 1.
do
	PASS="$PASS${MATRIX:$(($RANDOM%${#MATRIX})):1}"
	# ==> Very clever, but tricky.

	# ==> Starting from the innermost nesting...
	# ==> ${#MATRIX} returns length of array MATRIX.

	# ==> $RANDOM%${#MATRIX} returns random number between 1
	# ==> and [length of MATRIX] - 1.

	# ==> ${MATRIX:$(($RANDOM%${#MATRIX})):1}
	# ==> returns expansion of MATRIX at random position, by length 1. 
	# ==> See {var:pos:len} parameter substitution in Chapter 9.
	# ==> and the associated examples.

	# ==> PASS=... simply pastes this result onto previous PASS (concatenation).

	# ==> To visualize this more clearly, uncomment the following line
	                 echo "$PASS"
	# ==> to see PASS being built up,
	# ==> one character at a time, each iteration of the loop.

	let n+=1
	# ==> Increment 'n' for next pass.
done

echo "$PASS"      # ==> Or, redirect to a file, as desired.

exit 0
}
(( 0 )) && {	# This script creates a web gallery from specified images 

	#! /bin/sh # Filename: imggallery.sh 
	# Version: 0.1 
	# Date: Thu Feb 12 21:21:28 PST 2009 
	# Author: Ian MacGregor (aka ardchoille) 
	# License: GPL 
		echo "<html>" > index.html 
		echo "<head>" >> index.html 
		echo "<title>My Images</title>" >> index.html 
		echo "</head>" >> index.html 
		echo "<body>" >> index.html 
		echo "<h1> My Images</h1>" >> index.html 
		for img in *.jpg
		do
			echo $img convert -scale 120 $img thumb-$img mogrify -scale 640 $img 
			echo "<a href=\"$img\"><img src=\"thumb-$img\"></a>" >> index.html 
		done 
		echo "</body>" >>index.html 
		echo "</html>" >>index.html
}
(( 0 )) && {	# A script from Ted Tso.

	# From: Theodore Tso.  https://www.redhat.com/archives/ext3-users/2008-January/msg00032.html
	# On Tue, Jan 22, 2008 at 02:34:35PM -0800, Valerie Henson wrote:
	# > ... the ext3 defaults for forcing a file system check are a little
	# > too conservative for many modern use cases. ...
	# Yeah.  To the extent that people are using devicemapper/LVM
	# everywhere, there is a much better solution:
	# e2croncheck

	VG=closure
	VOLUME=root
	SNAPSIZE=100m
	EMAIL=tytso mit edu

	TMPFILE=`mktemp -t e2fsck.log.XXXXXXXXXX`	#  Use user’s TMPDIR env var if set, else, use /tmp.


	set -e
	START="$(date +'%Y%m%d%H%M%S')"
	lvcreate -s -L ${SNAPSIZE} -n "${VOLUME}-snap" "${VG}/${VOLUME}"

	if	nice logsave -as $TMPFILE e2fsck -p -C 0 "/dev/${VG}/${VOLUME}-snap" && \
		nice logsave -as $TMPFILE e2fsck -fy -C 0 "/dev/${VG}/${VOLUME}-snap"
	then
		echo 'Background scrubbing succeeded!'
		tune2fs -C 0 -T "${START}" "/dev/${VG}/${VOLUME}"
	else
		echo 'Background scrubbing failed! Reboot to fsck soon!'
		tune2fs -C 16000 -T "19000101" "/dev/${VG}/${VOLUME}"
		if test -n "EMAIL"; then 
			mail -s "E2fsck of /dev/${VG}/${VOLUME} failed!" $EMAIL < $TMPFILE
		fi
	fi

	lvremove -f "${VG}/${VOLUME}-snap"
	rm $TMPFILE
}
(( 0 )) && {	# get a handle on links.
	# how many?  Dirs or files?
	# do all resolve to a non-link destination
	# any other questions?

	# How many?  Run as root.
	# echo ; for D in /bin /boot /etc /lib /root /sbin /selinux /usr /var ; do echo -n "  $D   "; find $D -type l |wc -l; done ; echo
	# prints:
	# /bin   19
	# /boot   1
	# /etc   687
	# /lib   88
	# /root   0
	# /sbin   29
	# /selinux   0
	# /usr   13268
	# /var   3

	# find /usr -type l |while read LINK; do [ -d $LINK ] && ls -ld $LINK ; done |wc -l
	# prints: 245
	# find /usr -type l |while read LINK; do [ -f $LINK ] && ls -ld $LINK ; done |wc -l
	# prints: 13022
	# find /usr -type l |while read LINK; do [ ! -f $LINK ] && [ ! -d $LINK ] && ls -ld $LINK ; done |wc -l
	# prints: 1
	# 245 + 13022 + 1 --> 13268	# So, the link is either broken or to a file or to a dir.

	# How many of the links point to a dir?
	for DIR in /bin /boot /etc /lib /sbin /usr /var ; do find $DIR -type l |while read LINK; do [ -d $LINK ] && echo "  Dir: $LINK"; done ; done |wc -l
	# prints: 277

	# So, of the ~14100 links, 277 links point to dirs, the rest point to normal files or are broken.
}
(( 0 )) && {	# Setup user id and pw.  
	# NB, in example 1, the -p option requires the encrypted passwd
	# In example 2, the password is in plain text.

	# example 1
	PWD=`mkpasswd -l 8 -s 2`; export PWD
	echo "user = $1         password = $PWD"
	/usr/sbin/useradd -c "$2" -m -k /home/skeleton -n -p $PWD $1
	echo $PWD| passwd --stdin $1

	# example 2
	for user in user1 user2 user3 ;  do useradd $user ;  
	echo "password" |passwd --stdin $user ; done
}
(( 0 )) && {	# Hash a filename, use first 4 characters of hash to be dir structure for storage of file.

	# To put example.txt into a hashed file structure:
	echo -n example.txt |md5sum
	# prints: e76faa0543e007... -

	# Store file at .../e/7/6/f/example.txt
	# Or at .../e7/6f/example.txt
	# Use a benchmark to see which is better.
}
(( 0 )) && {	# 2-dim arrays	## This WORKS!  ## But, it is more like "nested arrays", not 2-dim arrays.
	# from <[email protected]> on CentOS list.

	myArray=("First" "Second" "Third")

	First=("Monday" "Tuesdays" "Wednesday")
	Second=("One" "Two" "Three")
	Third=("A" "B" "C")

	for i in ${myArray[@]}
	do
		echo "$i"
		for k in ${i}
		do
			echo "$i"
			eval TMP=\${$k[@]}
			echo ${TMP}
		done
	done
}
(( 0 )) && {	# Install CentOS on a USB key.  Not complete.
	# from	John Doe <[email protected]>, CentOS mailing list

	# Here's how I did my USB key (minus the kickstart part) but you need a linux (in a VM or from the live CD)...And you will have to change devices names!

	# 1. Create a small VFAT partition, then a big linux one:
	# fdisk /dev/sdg
	# 
	#     Device Boot      Start         End      Blocks   Id  System
	#  /dev/sdg1   *           1           3       23126    6  FAT16
	#  /dev/sdg2               4        1023     7873380   83  Linux

	mkfs.vfat -n BOOT /dev/sdg1
	mkfs.ext2 -m 0 -b 4096 -L DATA /dev/sdg2

	# Unplug/plug => /media/BOOT and /media/DATA

	# 2. Install syslinux on the VFAT partition:

	syslinux -s /dev/sdg1
	cd /media/BOOT
	cp -rv /mnt/cdrom/isolinux syslinux
	mv syslinux/isolinux.cfg syslinux/syslinux.cfg
	rm -f syslinux/isolinux.bin
	vi syslinux/syslinux.cfg

	# append method=hd:sda2:/centos

	# 3. Copy the CentOS ISOs to the linux partition (I had to use the CD ISOs because the DVD ones would get corrupt on my USB key for some reason):

	mkdir /media/DATA/centos
	for i in 1 2 3 4 5 6; 
	do 
		cp -v CentOS-5.3-i386-bin-${i}of6.iso /media/DATA/centos/; sync; 
	done
	for i in 1 2 3 4 5 6;
	do 
		diff /IOL/CENTOS_repo/CentOS-5.3-i386-bin-${i}of6.iso/ 
			media/DATA/centos/CentOS-5.3-i386-bin-${i}of6.iso; 
	done

	# 4. Optionaly (?), to be sure that it boots:

	# then: dd if=/usr/share/syslinux/mbr.bin of=/dev/sdg
}
(( 0 )) && {	# Setup CHS geometry to best utilize device space. 1.
	# From: [email protected]

	restrk=0
	if [ "$1" = -d ]; then
		restrk=1
		echo "Loss due to DOS compatibility mode considered"
		shift
	fi

	if [ -z "$1" -o "$1" = "-h" -o "$1" = "--help" ]; then
		echo "Usage: ${0##*/} [-d] total_sectors" >&2
		echo "  (Integer expression allowed for total_sectors)" >&2
		exit 1
	fi

	tsec=$(( ($1) + 0 ))    # Evaluate the input expression
	maxspcyl=$((63*255))    # Max possible sectors per cylinder
	mincyl=$(($tsec/$maxspcyl))
	[ $mincyl -lt 1 ] && mincyl = 1
	best_cap=0
	cyl=$mincyl
	full=

	trap "echo \"Interrupted at cyl count = \$cyl\"; exit" 2

	# echo " H  * S  * C  for $tsec total sectors:"
	echo " Heads * Sec/trk * Cylinders = Sectors (    bytes)"

	# while [ $cyl -le $(($tsec/8)) ]; do
	while [ $cyl -le 1600 ]; do
		cylsize_p=$(($tsec/$cyl))
		minspt=$(($cylsize_p/255))
		[ $minspt -gt 63 ] && minspt=63
		[ $minspt -lt 1 ] && minspt=1
		spt=$minspt
		while [ $spt -le 63 ]; do
			hd=$(($cylsize_p/$spt))			# Heads
			[ $hd -gt 255 ] && hd=255
			cap=$(($spt*$hd*$cyl))
			pcap=$(($spt*($hd*$cyl - $restrk)))
			if [ $pcap -ge $best_cap ]; then
				best_cap=$pcap
				[ $best_cap = $tsec ] && full=" 100%"
				# echo "$hd * $spt * $cyl = $pcap ($(($pcap*512)))$full"
				printf " %5d * %7d * %9d =  %d (%d)%s \n"  "$hd" "$spt" "$cyl" "$pcap"  $(($pcap*512)) "$full"
			fi
			spt=$(($spt+1))
		done
		cyl=$((cyl+1))
	done
}
(( 0 )) && {	# Setup CHS geometry to best utilize device space. 0.

#!/bin/bash
########
#Brute force searches for the CHS geometry that can best utilize a
#device with a given total sector count.  For each cylinder count,
#starting with the minimum possible and continuing until the
#cylinder size is reduced to just 8 sectors, it finds the best H
#and S count.  A line is written st stdout each time a geometry is
#found that is at least as good as the best one seen so far.
#(Sometimes a later geometry that yields the same sector count is
#in some way "nicer".)
#
#The "-d" option adjusts the calculation to account for the track
#that is wasted for the MBR in DOS compatibility mode.  Sometimes a
#smaller track size that wastes fewer sectors will be slightly
#better, though the maximum savings is minimal (55 sectors).
#
#For a large device, you will probably want to interrupt this
#before it runs to completion.  Evaluating geometries with millions
#of tiny cylinders can take hours, and those are not likely to be
#considered desirable.
#
#Released to the public domain 15 June 2009 by Robert Nichols
#   AT comcast.net I am rnicholsNOSPAM
#   (Yes, NOSPAM really is part of my email address.)
########

restrk=0
if [ "$1" = -d ]; then
   restrk=1
   echo "Loss due to DOS compatibility mode considered"
   shift
fi
if [ -z "$1" -o "$1" = "-h" -o "$1" = "--help" ]; then
   echo "Usage: ${0##*/} [-d] total_sectors" >&2
   echo "  (Integer expression allowed for total_sectors)" >&2
   exit 1
fi
tsec=$(( ($1) + 0 ))    # Evaluate the input expression
maxspcyl=$((63*255))    # Max possible sectors per cylinder
mincyl=$(($tsec/$maxspcyl))
[ $mincyl -lt 1 ] && mincyl = 1
best_cap=0
cyl=$mincyl
full=
trap "echo \"Interrupted at cyl count = \$cyl\"; exit" 2
echo " H  * S  * C  for $tsec total sectors:"
while [ $cyl -le $(($tsec/8)) ]; do
   cylsize_p=$(($tsec/$cyl))
   minspt=$(($cylsize_p/255))
   [ $minspt -gt 63 ] && minspt=63
   [ $minspt -lt 1 ] && minspt=1
   spt=$minspt
   while [ $spt -le 63 ]; do
       hd=$(($cylsize_p/$spt))
       [ $hd -gt 255 ] && hd=255
       cap=$(($spt*$hd*$cyl))
       pcap=$(($spt*($hd*$cyl - $restrk)))
       if [ $pcap -ge $best_cap ]; then
           best_cap=$pcap
           [ $best_cap = $tsec ] && full=" 100%"
           echo "$hd * $spt * $cyl = $pcap ($(($pcap*512)))$full"
       fi
       spt=$(($spt+1))
   done
   cyl=$((cyl+1))
done
}
(( 0 )) && {	# diff sort 2 files, w/o intermediate files.

	diff <(sort file1) <(sort file1) |less
}
(( 0 )) && {	# take a snapshot of file state before an upgrade or change.

	find . -type f -execdir md5sum {} \; | sort > /tmp/previous

	# Do the same after with a different file name and use diff
}
(( 0 )) && {	# debug keyboard and mouse events.

	echo
	# at cli: xev	# X events
	# note key press event and key release event.
	# Use xmodmap to remap keys.
}
(( 0 )) && {	# play with exec.  Burp!  Could not get to work.  This does work.

	DIR=/home/ja/temp/test-exec
	mkdir -p $DIR
	LOG=$DIR/log

	[ -f $LOG ] && rm $LOG
	for X in {1..5}
	do
		echo "This is line $X of a log file." >> $LOG
	done

	log_header() { echo "Script started"; }
	log_footer() { echo "Script stopped"; }
	mail_logs()  { cat ${LOG}; }

	(
		log_header
		mail_logs
		log_footer
	) | /bin/mail -s "My Mail Subject, 9" ja

	[ -f $LOG ] && rm $LOG
	[ -d $DIR ] && rmdir $DIR
}
(( 0 )) && {	# another way to do "while read"

	# create a file where each row has "string space anotherString"
	find ~ja/temp/klm -type f -printf "%k %p\n" > ~ja/temp/klm.new

	if [ -f ~ja/temp/klm.old ]; then
		cat ~ja/temp/klm.old | while read LINE
		do
			set $LINE
			OLDSIZE=$1
			OLDFILE=$2

			NEWSIZE=`grep "$OLDFILE\$" ~ja/temp/klm.new | cut -d " " -f1`

			if [ -n "$NEWSIZE" -a "$OLDSIZE" != "$NEWSIZE" ]; then
			  echo "$OLDFILE: $OLDSIZE => $NEWSIZE"
			fi
		done
	fi
	mv -f ~ja/temp/klm.new ~ja/temp/klm.old
}
(( 0 )) && {	# flash-plugin diagnosis

	rpm -q flash-plugin
	ls -l /usr/lib/mozilla/plugins
	mozilla-plugin-config -l
}
(( 0 )) && {	# play with the "select" builtin.

	echo
	echo "This script can make any of the files in this directory private."
	echo "Enter the number of the file you want to protect:"

	PS3="Your choice: "
	QUIT="QUIT THIS PROGRAM - I feel safe now."
	touch "$QUIT"

	# select FILENAME in *;					# works.
	# select FILENAME in *.klm *.;				# does NOT work. looks for a file "*.klm"
	select FILENAME in $(cd ~ja/temp/klm; ls *.klm *.)	# does NOT work.
	do
		case "$FILENAME" in
		"$QUIT")	echo "Exiting."
				break				;;

	              *)	echo "You picked $FILENAME ($REPLY)"
				chmod go-rwx "$FILENAME"	;;
		esac
	done
	rm "$QUIT"

}
(( 0 )) && {	# traceroute + ping ~= mtr
	/usr/sbin/mtr -c 10 -r centos.org

	# prints:
	# hudson.brc.localnet               Snt: 10    Loss%  Last   Avg  Best  Wrst StDev
	# 192.168.1.1                                   0.0%   0.5   0.5   0.4   1.0   0.2
	# c-67-172-184-1.hsd1.ca.comcast.net            0.0%   6.1   7.7   6.1   9.2   1.0
	# [...]
	# pod22e_aw.layeredtech.com                     0.0%  55.5  57.4  55.2  67.7   3.7
	# ???                                          100.0   0.0   0.0   0.0   0.0   0.0
	# 162.194.232.72.static.reverse.ltdomains.com  10.0%  56.4  55.9  55.2  56.8   0.6

	# From CentOS list: If the trace gets beyond the "???", 
	# that's sufficient to imply the packets get through,
	# since not all routers respond to the ICMP tests.
}
(( 0 )) && {	# verify rkh

	gpg --verify rkhunter-1.3.2.tar.gz.asc rkhunter-1.3.2.tar.gz
	# prints: gpg: Signature made Wed 27 Feb 2008 18:17:49 SAST using RSA key ID 26447505

	# use ID number
	gpg --keyserver subkeys.pgp.net --recv-keys 26447505
}
(( 0 )) && {	# convert postscript doc to ascii.

	/usr/bin/ps2ascii /usr/share/doc/iproute-2.6.18/ss.ps |less
}
(( 0 )) && {	# Determine what changes an update caused.

	# From: Bill Campbell <[email protected]>
	# On Tue, Feb 24, 2009, Joseph L. Casale wrote:
	# >Is there anything I can use to take an inventory of the filesystem
	# >before and after some process to see what's changed?

	# I frequently do something like this:

	touch /tmp/copyctrl
	# do update here
	find / ! -type d -newer /tmp/copyctrl | sort > /tmp/changelist
}
(( 0 )) && {	# Add sequential numbering as a prefix.

	# Given a dir with filenames that are sorted,
	# rename to add sequential numbering as a prefix.

	SEQ=0
	DIR='/home/ja/public/in_work/Windows/test'
	for F in  ${DIR}/*.jpg
	do
		G=$(basename $F)			# 000_truck_1.jpg
		H=$(echo $G |sed -e 's;[0-9]*_;;')	# truck_1.jpg
		SEQ=$((SEQ + 1))			#   1 or  23 or ...
		I=$(printf "%03d\n" "${SEQ}")		# 001 or 023 or ...

		echo $F ; #echo $G ; echo $H ; echo "$I"
		echo "${DIR}/${I}_${H}"			# dir/001_truck_1.jpg
		echo

		mv $F "${DIR}/${I}_${H}"
	done

	# 1. make the printf padding large enough to avoid an renaming problems.
	# 2. after this executes, remove any un-needed leading zeros.
}
(( 0 )) && {	# when doing multiple grep commands, make it easy to change the "pattern" part.

	</data/playlists/fav.mplayer grep Maes

	# then use up arrow to recall last line; then change last word.

	</data/playlists/fav.mplayer grep Rondo
}
(( 0 )) && {	# provide a "tree-like" view of dir structure from CURRENT DIR.

	# first sed expression replaces content between slashes, eg "/wxyz/" with "  |"
	# second expr adds a dash in front of dir names.

	find . -type d |sed -e "s/[^-][^\/]*\//  |/g"  -e "s/|\([^ ]\)/|-\1/"
}
(( 0 )) && {	# Get the card and device numbers.

	# > card 0: NVidia [HDA NVidia], device 3: NVIDIA HDMI [NVIDIA HDMI]
	# >   Subdevices: 1/1
	# >   Subdevice #0: subdevice #0
	# >
	# > card 2: HDMI [HDA ATI HDMI], device 3: ATI HDMI [ATI HDMI]
	# >   Subdevices: 0/1
	# >   Subdevice #0: subdevice #0

	# From: John Doe <[email protected]> on CentOS list.

	echo "  Output of aplay -l"
	aplay -l

	echo
	echo "  The card and device numbers"
	# aplay -l | grep HDMI | tr ":," "\n" | grep "^card\|^ device" | awk ' { print $2 } '
	#                           ^^^^
	# the tr command breads the single line into multiple lines for easier access.  Nice.


	# for my sound card, this works:
	aplay -l |grep ^card |tr ',:' "\n" |egrep '^card|^ device' |awk '{print $2}'
	# but the output is in a vertical format, which is not real handy.
}
(( 0 )) && {	# Centos messages re failure of install at the partitioning part.

	echo
	# David Hrb?c wrote: are those disks totally empty or there are some partitions? 
	# Try to look at them with fdisk. BTW sometimes Anaconda fails on disks with partitions. 
	# Deleting partitions helps before install, sometimes I have to 
	# "create a new empty DOS partition table" with fdisk

	# From: John R Pierce <[email protected]> 
	# Subject: Re: [CentOS] getting Centos on "used" rackable systems 1U withdualOpteron 248 HE
	# or my old standby, boot the centos cd to single user mode, and execute
	#
	#   dd if=/dev/zero of=/dev/sda bs=1024 count=1024
	#
	# this zeros the first megabyte of the disk, wiping all traces of partition tables.
	# power cycle to clear the state of -everything-, *then* boot the installer...

}
(( 0 )) && {	# compare the number of files in a tree on backup hdd to tree on main storage.
	# may need to do as root, depending on tree permissions.
	# Weed out ~/.<dirname>

	cd /media/disk/backups/ja
	find . -type f |grep -v '\./\.' |sort >/root/list_of_WD640GB

	cd ~ja
	find . -type f |grep -v '\./\.' |sort >/root/list_of_home_ja
}
(( 0 )) && {	# convert seconds to human-readable.

	for SEC in 3 63 3603 90003	# 3sec, 1min3sec, 1hour3sec, 1day1hour3sec
	do
		ds=$((SEC % 60))
		dm=$(((SEC / 60) % 60))
		dh=$(((SEC / 3600) % 24))
		dd=$((SEC / 86400))
		printf '  Seconds: %8d \tDays Hours Minutes Seconds: %2d %02d %02d %02d\n' $SEC $dd $dh $dm $ds
	done

}
(( 0 )) && {	# Measure the time taken by parts of a script.
	# Thanks: Mitch Frazier at http://www.linuxjournal.com/content/use-date-command-measure-elapsed-time

	function timer()
	{
		if [[ $# -eq 0 ]]
		then
			# No arguments.  Print starting value.
			echo $(date '+%s')
		else
			# At least 1 argument. Print elapsed time.
			local  stime=$1
			etime=$(date '+%s')

			if [[ -z "$stime" ]]; then stime=$etime; fi

			dt=$((etime - stime))
			ds=$((dt % 60))
			dm=$(((dt / 60) % 60))
			dh=$((dt / 3600))
			printf '%d:%02d:%02d' $dh $dm $ds
		fi
	}
	t=$(timer)
	read -p '  Enter when ready...' p
	printf  '  Elapsed time: %s\n' $(timer $t)
}
(( 0 )) && {	# Convert standard time to unix time

	date --date="2009-06-18 18:57" +%s
}
(( 0 )) && {	# note the arithmetic expression that controls the loop.

	for (( c=1; c<=5; c++ )); { echo "  Hi, $c times"; }
}
(( 0 )) && {	# setup test cases for files and dirs with embedded double-spaces.

	LOC=~ja/temp/test-cases
	rm -rf "${LOC}"
	mkdir "${LOC}"
	touch "${LOC}/a bb  c"		# verbally: a, space, b, b, space, space, c

	mkdir "${LOC}/a aa  a"		# verbally: a, space, a, a, space, space, a
	touch "${LOC}/a aa  a/b bb  b"	#
	touch "${LOC}/a aa  a/c cc  c"	#

	# When using the "find | while" construct, 
	# double spaces are replaced by a single space.
	#
	find "${LOC}" -type f |while read -a F				### double spaces test code.
	do
		echo "  F: ${F[*]}"
		[   -f "${F[*]}" ] && echo "  IS a file"
		[ ! -f "${F[*]}" ] && echo "  NOT a file"
	done
	echo

	# When using the "IFS, find" approach,
	# the double spaces are preserved. Root! Root!
	#
	SaveIFS=$IFS
	IFS='\
'
	for G in $(find "${LOC}" -type f)
	do
		echo "  G: $G"
		[   -f "$G" ] && echo "  IS a file"
		[ ! -f "$G" ] && echo "  NOT a file"
	done
	IFS=$SaveIFS
	echo

	# When using the "ls" approach,
	#
	ls -d "${LOC}/a aa  a"		# preserves double spaces.
	ls    "${LOC}/a aa  a"		# preserves double spaces.
	echo
	ls -d "${LOC}/a aa  a" |while read -a H; do echo "${H[*]}"; done	# does NOT preserve double spaces.
	ls    "${LOC}/a aa  a" |while read -a H; do echo "${H[*]}"; done	# does NOT preserve double spaces.
	echo
}
(( 0 )) && {	# Transfer an entire filesystem from one machine to another.
	# (Thanks: http://www.linuxjournal.com/content/copying-filesystem-between-computers)
	#
	# For example, when you get a new computer, do the following steps.
	# 1) Boot both PCs with any Linux live CD (for example, Knoppix), and make sure they can access each other via the network.
	# 2) On the source machine, mount the partition containing the filesystem to be copied, and start the transfer using netcat and tar:

	# tar options:	c=create, z=zip, p=perserve-permissions, s=same-order, f=file
	# pv options:	b=
	cd /mnt/sda1
	tar -czpsf - . | pv -b | nc -l 3333

	# 3) On the destination machine, mount the partition to receive the filesystem, and start the process:

	cd /mnt/sda1
	nc 192.168.10.101 3333 | pv -b | tar -xzpsf -

	# The nc (netcat) command is used for any kind of TCP connections between two hosts. 
	# The pv (progress viewer) command is used to display the progress of the transfer. 
	# tar is used to archive the files on the source machine and un-archive them on the destination.

	# Another, unrelated, example:

	tar zcf - user | pv /bin/gzip > /tmp/backup.tar.gz
	# 59.7kB 0:00:00 [ 223MB/s] [===========================================>] 100%

	# for doing what you expect, you need to do something like:
	cd /home
	size=`du -bs user | sed s/[[:space:]].*$//g`
	tar zcf - user | pv -s $size | gzip > /tmp/backup.tar.gz
	# 366MB 0:00:33 [ 11MB/s] [=================================>] 100%

	# And you will maybe get a “not so high” rate…
}
(( 0 )) && {	# How to turn off error messages that are written to the console.

	# In a VC:
	setterm --msg off

	# I have NOT tried this yet.  The nfs messages to console on fundy have stopped and I don't know why.
	# If the messages start again, try this.
}
(( 0 )) && {	# Monitor /var/log/yum for changes.

	FILE=/var/log/yum.log
	RUN=/var/run/yum
	CONTROL=/home/ja/etc/var/control/yum.log.$(hostname -s)

	[ ! -f ${CONTROL} ] \
		&& touch -r ${FILE} ${CONTROL} \
		&& chown ja:ja ${CONTROL}

	! [ ${FILE} -nt ${CONTROL} ] && exit 1		# If file is NOT newer than control, exit.
	[ -f ${RUN} ] && exit 1				# bailout if yum is running right now.

	touch -r $FILE $CONTROL

	echo -e "\tCarry out the required operations HERE."
}
(( 0 )) && {	# Monitor a file for changes.

	[ $# -lt 1 ] && echo "  Kindly specify a file to monitor" && exit 1
	[ ! -f $1 ] && echo "  NOT a file: $1" && exit 1
	BN=$(basename $1)
	M="/home/ja/temp/filechanges/monitor-$BN"
	echo "  BN: $BN   M: $M"

	[ ! -f $M ] && echo "  Creating monitor: $M" && touch -r $1 $M

	[ $1 -nt $M ] && echo -e "\t$1 is newer than $M. \n\tCarry out your required operations."
	touch -r $1 $M
}
(( 0 )) && {	# Searching command history.
	: <<-MYCOMMENTS

	From: "Filipe Brandenburger" <[email protected]>

	> Which command I can only select "traceroute 192.168.0.5" to run?

	I would type "Ctrl-R" (interactive search history starting with more
	recent events), then type "trace", then type "Ctrl-R" again until I
	find the command I am looking for, in your case, 4 times. Once you
	start using "Ctrl-R" you will probably never want to use "history |
	grep ..." and "!..." again.

	More:

	ctrl-r		Start reverse incremental history search mode
	When in reverse incremental history search mode:
	- type until the desired matching command is found

	Enter		Retrieve and execute the  command.
	ctrl-j or Esc	Retrieve the command and allow command edit.

	ctrl-g		Cancel,
	ctrl-c		Cancel,

	From man bash:

	!	Start  a history substitution, except when followed by a blank,
		newline, carriage return, = or ( (when the extglob shell option
		is enabled using the shopt builtin).
	!n	Refer to command line n.
	!!	Refer to the previous command.  This is a synonym for ‘!-1’.
	!string	
		Refer to the most recent command starting with string.
	!?string[?]
		Refer to the most recent command containing string.  The trail-
		ing ? may be omitted if string is followed immediately by a newline.

	MYCOMMENTS
}
(( 0 )) && {	# play with multiple concurrent reads.  thanks: www.linuxjournal.com

	# have 2 files, with an equal number of lines each.
	# combine line 1 from file A with line 1 from file B.  etc...

	A=~ja/temp/fileA.$$
	echo -e "f1 1\nf1 2\nf1 3\nf1 4" >$A

	B=~ja/temp/fileB.$$
	echo -e "f2 1\nf2 2\nf2 3\nf2 4" >$B

	while read f1 <&7		## double spaces naf.
	do
		read f2 <&8
		echo $f1 $f2
	done \
		7<$A 8<$B

	# prints:
	# f1 1 f2 1
	# f1 2 f2 2
	# f1 3 f2 3
	# f1 4 f2 4

	rm $A $B
}
(( 0 )) && {	# powertop recommends to disable dvd polling on hudson (F8):
	#	hal-disable-polling --device /dev/scd0
	# to enable:
	#	hal-disable-polling --enable-polling --device /dev/scd0

	# how to deterine scd0 or whatever ??

	# dvddp = DVD Disable Polling
	alias dvddp hal-disable-polling --enable-polling --device /dev/scd0
}
(( 0 )) && {	# using "set -x" 
	# prior to execution, set PS4 to a helpful value, eg: export PS4="DEBUG => "

	set -x

	# from man bash:
	# set -x
	#	After expanding each simple command, for command, case command, select command,	or
	#	arithmetic for command, display the expanded value of PS4, followed by  
	#	the command and its expanded arguments or associated word list.

	# loop through and display some test statements
	_X=1
	while [[ ${_X} -le 4 ]]
	do
		[[ ${_X} -lt 2 ]] && echo "X is less than 2!"

		_Y=`expr ${_X} + 1`

		if [[ ${_Y} -eq 3 ]]
		then
			echo "Y is now equal to ${_Y}"
		fi

		_X=${_Y}
	done

	: <<-MYCOMMENTS
	# Prints:
	+ _X=1
	+ [[ 1 -le 4 ]]
	+ [[ 1 -lt 2 ]]
	+ echo 'X is less than 2!'
	X is less than 2!
	++ expr 1 + 1
	+ _Y=2
	+ [[ 2 -eq 3 ]]
	+ _X=2
	+ [[ 2 -le 4 ]]
	+ [[ 2 -lt 2 ]]
	++ expr 2 + 1
	+ _Y=3
	+ [[ 3 -eq 3 ]]
	+ echo 'Y is now equal to 3'
	Y is now equal to 3
	+ _X=3
	+ [[ 3 -le 4 ]]
	+ [[ 3 -lt 2 ]]
	++ expr 3 + 1
	+ _Y=4
	+ [[ 4 -eq 3 ]]
	+ _X=4
	+ [[ 4 -le 4 ]]
	+ [[ 4 -lt 2 ]]
	++ expr 4 + 1
	+ _Y=5
	+ [[ 5 -eq 3 ]]
	+ _X=5
	+ [[ 5 -le 4 ]]
	+ exit
MYCOMMENTS
	exit
}
(( 0 )) && {	# Is the current version of rrdtool LT or GT 1.2.7?
	# Scripts will fail!!

	CURR=$(rrdtool -h |head -n 1 |cut -d' ' -f2)

	[[ "$CURR" < "1.2.7" ]] && echo "The current version, $CURR, is less than 1.2.7"
}
(( 0 )) && {	# play with RANDOM

	echo $(( $RANDOM ))		# prints: 0 thru 32767
	echo $(( 5 % 5 ))		# prints: 0
	echo $(( $RANDOM % 100 ))	# prints: 0 thru 99
	expr $(( $RANDOM % 100 )) + 1	# prints: 1 thru 100
	# for X in {1..10000}; do V=$(expr $(( $RANDOM % 100 )) + 1); [ $V -eq 0 ] && echo $V; done	## 10,000 times.  nothing prints.
}
(( 0 )) && {	# Search the "man" pages for a keyword
	# man -k <keyword>

	man -k which |grep ^which
}
(( 0 )) && {	# Split a file into parts, based on a pattern match of some lines.

	DIR=/home/ja/temp/csplit-test ; mkdir -p $DIR ; cd $DIR
	F=./source.txt
	cat <<- FILEBOUNDARY > $F
xxx1
aaa,bbb,ccc,ddd
aba,bab,cdc,dcd
xxx2
eee,fff,ggg
xxx3
hhh,iii
xxx2
eef,ffg,gge,fff
FILEBOUNDARY

	# Match on lines that start with "xxx"	NB: there are 2 xxx2 parts.

	# spit out file parts.
	recsep='xxx[0-9]*'
	numrecs=$(grep -c "^${recsep}" $F)
	if [ ${numrecs} -le 1 ]
	then
		echo "Only one type of record, not splitting file." && exit 0
	elif [ ${numrecs} -eq 2 ]
	then
		# %REGEXP%[OFFSET] means: skip to, but not including a matching line
		# /REGEXP/[OFFSET] means: copy up to but not including a matching line
		# csplit -skf data $F "%^${recsep}%" "/^${recsep}[0-9]*/"	# the "[0-9]*" is not needed.  always evals to no-match.
		csplit -skf data $F "%^${recsep}%" "/^${recsep}/"
	else
		splitcount=$(expr ${numrecs} - 2)
		# {INTEGER} means: repeat the previous pattern the specified number of times
		csplit -skf data $F "%^${recsep}%" "/^${recsep}/" \{${splitcount}\}
	fi

	# combine parts with the same pattern match. (eg: xxx2)
	for I in $(ls data*)
	do
		O=$(head -n 1 $I)
		grep -v $O $I >> $O
	done
}
(( 0 )) && {	# Test an IP address for validity:

	function valid_ip()
	{
		local  ip=$1 stat=1

		if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]
		then
			OIFS=$IFS		# save Internal Field Separator
			IFS='.'
			ip=($ip)		# create array for ip parts.
			IFS=$OIFS
			[[ ${ip[0]} -le 255 \
				&& ${ip[1]} -le 255 \
				&& ${ip[2]} -le 255 \
				&& ${ip[3]} -le 255 ]]
			stat=$?			# status of logical expr.
		fi
		return $stat			# returns status of logical expr.
	}

	ips='	4.2.2.2		a.b.c.d		192.168.1.1
		0.0.0.0		255.255.255.255	255.255.255.256
		192.168.0.1	192.168.0	1234.123.123.123
	'
	for ip in $ips
	do
		#  valid_ip IP_ADDRESS
		#  if [[ $? -eq 0 ]]; then echo good; else echo bad; fi
		if valid_ip $ip; then stat='good'; else stat='bad'; fi		# check return status

		printf "%-20s: %s\n" "$ip" "$stat"
	done
}
(( 0 )) && {	# Note relational expression.  First parm MATCHES prog OR second parm EQUALS 4.

	rpcinfo -p |while read -a L					# double spaces naf.
	do
		[[ ${L[0]} =~ prog || ${L[1]} -eq 4 ]] \
			&& printf "%10s %4s %5s %6s  %s \n" ${L[*]}
	done
}
(( 0 )) && {	# overwrite a file with random data.  Do it 10 times.

	# First, find the number of bytes in the file.  Eg, ll /root/Trash
	# Then use that value.  Eg, bs=111110

	# Options:
	#	notrunc		do not truncate the output file
	#	noerror		continue after read errors

	F=/root/Trash

	#for N in $(seq 10); do dd if=/dev/urandom of=$F bs=111110 count=1 conv=notrunc,noerror; done

}
(( 0 )) && {	# play with bash built-in regular expression comparison operator "=~".

	# Thanks: http://www.linuxjournal.com/content/bash-regular-expressions
	#
	# Execute: $0 'aa(b{2,3}[xyz])cc' aabbxcc aabbcc
	# Prints:
	#	regex: aa(b{2,3}[xyz])cc
	#	aabbxcc matches
	#	  capture[1]: bbx
	#	aabbcc does not match
	# Matches are assigned to an array BASH_REMATCH. 
	# The entire match is assigned to BASH_REMATCH[0], the first sub-pattern to BASH_REMATCH[1], etc..

	[ $# -lt 2 ] && echo "Usage: $0 PATTERN STRINGS..." && exit 1

	regex=$1
	echo -e "regex: $regex \n"
	shift

	for S in $@
	do
		if [[ $S =~ $regex ]]
		then
			echo "$S matches"

			# for SubPattern in ${BASH_REMATCH[@]}; do echo "  $SubPattern"; done

			N=${#BASH_REMATCH[*]}
			N=$((N-1))
			for i in $( seq 0 $N ) ; do echo "  capture[$i]: ${BASH_REMATCH[$i]}" ; done
		else
			echo "$S does not match"
		fi
		echo
	done
}
(( 0 )) && {	# cli packet capture

	echo
	# tshark udp port 1234
	# or
	# tcpdump -i <interface> udp port <port>
	#
	# or: tcpdump -i eth0 port 4957 -nn -vv
	# or: tcpdump -i ethX -p -s 0 -w /path/to/4957.trace.pcap port 4957
	# tcpdump options:
	#	-w=write packets to a file
	#	-p=Do NOT put interface in promiscuous mode.
	#	-s 0=snarf 0 bytes of data from each packet,rather than the default 68.  see man page.
	#	-n=Do NOT convert host addresses to names.  Avoids dns lookup.
	#	-nn=Do NOT convert protocol and port numbers to names either.
	#	-vv=verbose level. 

	# Other info from CentOS list.

	tcpdump -i eth0 -s 0 -w capture.cap	# Creates file capture.cap. Read with wireshark.

	tcpdump -i eth0 -s 0 -w capture.cap not port 22		# will drop all SSH traffic
	# tcpdump -i eth0 -s 0 -w capture.cap not host <ip>	# will drop traffic to/from <ip>

}
(( 0 )) && {	# feed passwords to an app.

	# > It reads the first insertion, but asks for the second.

	(echo secret; echo secret) | pure-pw ...

	# Or: echo -e 'secret\nsecret' | pure-pw

	# Or: pure-pw <<EOF
	# secret
	# secret
	# EOF

}
(( 0 )) && {	# find MAC addresses of hosts on local network.

	/sbin/arp -a		# all hosts

	# prints:
	# fundy.brc.localnet (192.168.1.15) at 00:1A:4D:4A:92:59 [ether] on eth0
	# ? (192.168.1.1) at 00:18:39:5B:75:C0 [ether] on eth0

	# the "?" indicates that this host is not in /etc/hosts (at least, maybe more)

	nmap -sP -n 192.168.1.15	# run as root.

	# prints:
	# Starting Nmap 4.52 ( http://insecure.org ) at 2008-05-08 12:52 PDT
	# Host 192.168.1.15 appears to be up.
	# MAC Address: 00:1A:4D:4A:92:59 (Gigabyte Technology Co.)
	# Nmap done: 1 IP address (1 host up) scanned in 0.138 seconds

	cat /sys/class/net/eth0/address

	# On hudson, 2009.06.29, prints:
	# 00:1a:4d:56:7e:af
}
(( 0 )) && {	# Copy a CD or DVD with dd, linux journal, April 18th, 2008 by Mitch Frazier

	echo
	# If you need to copy a CD to your hard drive:
	# prompt@shell$  dd if=/dev/cdrom of=/path/to/cdcopy.iso

	# For a DVD:
	# prompt@shell$  dd if=/dev/dvd of=/path/to/dvdcopy.iso
}
(( 0 )) && {	# which cli commands are used most frequently ?

	history |awk '{a[$2]++} END{for(i in a){ printf "%5d\t%s \n",a[i],i}}' |sort -rn |head
}
(( 0 )) && {	# LABEL and UUID

	cat /etc/fstab |grep LABEL		# prints: LABEL=/boot /boot ext3 defaults 1 2  (squeezed spaces)
	findfs LABEL=/boot			# prints: /dev/sda1

	/lib/udev/vol_id /dev/sda1		# prints:
		# ID_FS_USAGE=filesystem
		# ID_FS_TYPE=ext3
		# ID_FS_VERSION=1.0
		# ID_FS_UUID=e7de78af-bee4-4c9a-a861-0c57c97eb0d0
		# ID_FS_UUID_ENC=e7de78af-bee4-4c9a-a861-0c57c97eb0d0
		# ID_FS_LABEL=/boot
		# ID_FS_LABEL_ENC=\x2fboot
		# ID_FS_LABEL_SAFE=boot

	# see also: /dev/disk/by-{id,label,path,uuid} on Fedora8.

	# using block id
	/sbin/blkid		# prints:
		# /dev/mapper/VolGroup00-LogVol01: TYPE="swap" UUID="eb64262e-1824-450d-b8bd-720759851c2a" 
		# /dev/mapper/VolGroup00-LogVol00: UUID="2946a991-25c5-49eb-97cf-572e8d89dfe2" SEC_TYPE="ext2" TYPE="ext3" 
		# /dev/sda1: LABEL="/boot" UUID="e7de78af-bee4-4c9a-a861-0c57c97eb0d0" SEC_TYPE="ext2" TYPE="ext3" 
		# /dev/VolGroup00/LogVol00: UUID="2946a991-25c5-49eb-97cf-572e8d89dfe2" SEC_TYPE="ext2" TYPE="ext3"
	# so, parse as needed.

	# or:
	tune2fs -l /dev/sda1 |egrep '^Filesystem UUID|^Filesystem volume'	# prints:
		# Filesystem volume name:   /boot
		# Filesystem UUID:          e7de78af-bee4-4c9a-a861-0c57c97eb0d0
}
(( 0 )) && {	# play with seq

	echo $(seq 4)				# prints: 1 2 3 4
	echo $(seq 1 4)				# prints: 1 2 3 4
	echo $(seq 2 2 8)			# prints: 2 4 6 8
	echo $(seq --format='Num: %g, ' 4)	# prints: Num: 1, Num: 2, Num: 3, Num: 4,
	echo $(seq --format=%003.f 1 12)	# prints: 001 002 003 004 005 006 007 008 009 010 011 012
	echo $(seq --separator=', ' 4)		# prints: 1, 2, 3, 4
	echo $(seq --equal-width 8 12)		# prints: 08 09 10 11 12
}
(( 0 )) && {	# compare seq and {..}

	message='Test Message'

	# for n in $(seq 0 9); do echo -en "$n "; done; echo
	# for n in {0..9};     do echo -en "$n "; done; echo
	### SAME output !!

	# for n in $(seq 0 $(expr ${#message} - 1)); do echo -en "$n "; done; echo
	# for n in {0..$(expr ${#message} - 1)};     do echo -en "$n "; done; echo
	### NOT same !!

	# So, ... do NOT plan on any expansion / intrepretation within {..} construct.
	# Do NOT even use a variable.
}
(( 0 )) && {	# Arguments with embedded spaces.
	#
	# from: Jacques B. jjrboucher at gmail.com
	# at:   http://lists.centos.org/pipermail/centos/2008-February/095012.html
	# Invoke eg: ./scriptname one "two three" four "five;six\"" seven eight 'nine ten'

	E_BADARGS=65
	[ ! -n "$1" ]  &&  echo "Kindly specify an argument."  &&  exit $E_BADARGS

	index=1				# Initialize count.
	echo -e "\nListing args with \$* (unquoted):"
	for arg in $*
	do
		echo "Arg #$index = $arg"
		let "index+=1"
	done
	echo "Breaks up args with embedded spaces."

	index=1				# Initialize count.
	echo -e "\nListing args with \"\$*\":"
	for arg in "$*"			# Doesn't work properly if "$*" isn't quoted.
	do
		echo "Arg #$index = $arg"
		let "index+=1"
	done
	echo "Entire arg list seen as single word."

	index=1				# Initialize count.
	echo -e "\nListing args with \"\$@\":"
	for arg in "$@"
	do
		echo "Arg #$index = $arg"
		let "index+=1"
	done
	echo "Arg list correctly seen as separate words."

	echo ; exit 0
}
(( 0 )) && {	# filenames with embedded spaces.

	Dir=~ja/temp/spaces
	[ -d $Dir ] || mkdir -p $Dir
	cd $Dir

	touch "one" "two" "one two" "one two three"
	for F in *; do echo $F; done		# prints 4 lines, as expected.

	for F in $(ls .); do echo  $F;  done	# prints 7 lines.
	for F in $(ls .); do echo "$F"; done	# prints 7 lines.
	for F in $(ls *); do echo "$F"; done	# prints 7 lines.

	for F in $@;   do echo $F; done		# prints nothing
	for F in $*;   do echo $F; done		# prints nothing
	for F in "$@"; do echo $F; done		# prints nothing
}
(( 0 )) && {	# info on eth0

	# must be root to run

	NIC=eth0
	echo -e "\t\"ethtool\" info for $NIC \n\t===================== \n"

	# -a=pause settings  -g=ring parms  -i=driver info  -k=offload settings and parms. -S=statistics.
	for OPTION in "" -a -g -i -k -S
	do
		echo -e "\n\n\t===== Option: $OPTION \n"
		/sbin/ethtool $OPTION $NIC
	done

	echo -e "\n\n\tFor more info, use iptraf."
}
(( 0 )) && {	# check for 64 vs 32

	echo -n "Running "
	RES=`uname -a | grep 64`

	if [ $? -eq 0 ]
	then  echo -n "64-bit "
	else  echo -n "32-bit "
	fi

	echo -n "operating system on a "
	RES=`cat /proc/cpuinfo | grep " lm "`	# lm is one of the flags.

	if [ $? -eq 0 ]
	then  echo -n "64-bit "
	else  echo -n "32-bit "
	fi

	echo "machine"				# machine =? cpu.
}
(( 0 )) && {	# Is DPMS enabled as an extension in my setup?

	xdpyinfo |grep DPMS

	# Is DPMS currently on?

	xset q
}
(( 0 )) && {	# find broken links.

	[ $# -lt 1 ] && echo -e "\tKindly specify a dir" && exit 1
	[ ! -d $1  ] && echo -e "\tNOT a dir: $1"	 && exit 1

	for i in $(find $1 -type l)		# From: "Christian Volker" <[email protected]> on CentOS list.
	do					# $1 directory to search
	       file $i | grep -q broken		# Exits with zero status if any match is found.

	       if [ $? -eq 0 ] ; then echo "Broken link: $i"; fi
	done
}
(( 0 )) && {	# list files as a quoted, comma-separated list.
	# m = full width with a comma separated list of entries.
	# Q = enclose entry names in double quotes.

	ls -Qm ~/bin/*.pl
}
(( 0 )) && {	# remove duplicates but preserve original order if items.

	F=~/temp/numbers
	cat > $F <<-EOF
		one
		two
		three
		one
		three
		four
	EOF

	nl numbers |sort -k2 -u |sort -n |cut -f2
}
(( 0 )) && {	# man file to text file.

	man foo |col -b > foo.txt
}
(( 0 )) && {	# see if the centos torrent site is up.

	nmap -sT -p6969 -vv torrent.centos.org

	# port scan
	nmap -p 1-1024 192.168.1.10

	# Prints:
	# Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2010-09-13 17:08 PDT
	# Note: Host seems down. If it is really up, but blocking our ping probes, try -P0
	# Nmap finished: 1 IP address (0 hosts up) scanned in 3.003 seconds

	# post scan, treats all hosts as online.
	nmap -p 1-1024 -P0 192.168.1.10

	# Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2010-09-13 17:09 PDT
	# Interesting ports on pacific.brc.localnet (192.168.1.10):
	# Not shown: 1022 filtered ports
	# PORT    STATE  SERVICE
	# 22/tcp  open   ssh
	# 631/tcp closed ipp
}
(( 0 )) && {	# get a list of IP addresses on network

	# -sP is ping scanning.
	# -sS/sT/sA/sW/sM: TCP SYN/Connect()/ACK/Window/Maimon scans
	# -P0: Treat all hosts as online -- skip host discovery
	# -O: Enable OS detection
	# -A  is os scanning, version detection, and more.
	# -T4 is agressive timing.  ie hammer the hosts.
	# -p <port ranges>: Only scan specified ports
	# -n/-R: Never do DNS resolution/Always resolve [default: sometimes]

	nmap -sP 192.168.1.0/24

	# prints:
	#	Starting nmap 3.70 ( http://www.insecure.org/nmap/ ) at 2007-12-16 15:49 PST
	#	Host 192.168.1.1 appears to be up.
	#	MAC Address: 00:18:39:5B:75:C0 (Unknown)
	#	Host pacific.brc.localnet (192.168.1.10) appears to be up.
	#	Host baffin.brc.localnet (192.168.1.11) appears to be up.
	#	MAC Address: 00:1A:4D:40:E7:F1 (Unknown)
	#	Host quiettoo.brc.localnet (192.168.1.12) appears to be up.
	#	MAC Address: 00:0F:EA:23:9C:64 (Giga-Byte Technology Co.)
	#	Host fundy.brc.localnet (192.168.1.15) appears to be up.
	#	MAC Address: 00:1A:4D:4A:92:59 (Unknown)
	#	Nmap run completed -- 256 IP addresses (5 hosts up) scanned in 5.624 seconds
}
(( 0 )) && {	# FUNCNAME is an array that has a list of functions being executed, as far back as "main".
	# "caller" identifies where a subroutine was called from.

	test_a(){ echo "My name is test_a" ; caller 0 ; echo ${FUNCNAME[@]} ; echo ${BASH_LINENO[@]} ; }
	test_b()
	{ 
		echo "My name is test_b"; 

		caller 0 ; echo ${FUNCNAME[@]} ; echo ${BASH_LINENO[@]} ; 

		test_a;				# this is line 18

		# this section turns out to be redundant.
		caller 0 ; echo ${FUNCNAME[@]} ; echo ${BASH_LINENO[@]}; 
	}
	test_b					# this is line 24.

	# prints:
	#	My name is test_b
	#	24 main /home/ja/bin/code_bash.sh	# caller
	#	test_b main				# funcname
	#	24 0					# lineno
	#	My name is test_a
	#	18 test_b /home/ja/bin/code_bash.sh
	#	test_a test_b main
	#	18 24 0
	#	24 main /home/ja/bin/code_bash.sh	# redundant with above output from caller
	#	test_b main				# redundant with above output from funcname
	#	24 0					# redundant with above output from lineno
}
(( 0 )) && {	# backups with split.
	# t ~= 240K.  bzips to ~63K.

	cat t |bzip2 |(split -b 10k - dump.bz2.)
	# creates 7 files named dump.bz2.xa{a,b,c,d,e,f,g}, each 10k except the last.
	# "cat t |bzip2 |tee >(split -b 10k - dump.bz2.) |md5sum > t.md5" does not finish, but it works.

	# Thanks: Ray Van Dolson <[email protected]>
	mkfifo t.fifo
	(split t.fifo -b 10k) &
	cat t |bzip2 |tee t.fifo |md5sum
	rm -f t.fifo
 
	# create a pipe.  in the background, split the pipe.
	# then create the splits and the md5sum.
}
(( 0 )) && {	# get bios, system, ... info.  run as root.

	/usr/sbin/dmidecode |less		# all info
	/usr/sbin/dmidecode -s bios-vendor	# string.  from a list in man page
	/usr/sbin/dmidecode -t bios		# type.
	/usr/sbin/dmidecode -t 1,2,3		# type

	hdparm -i /dev/sda			# get hard disk info reported during boot. Includes serial number for a WD disk.
	hdparm -i /dev/dvd			# info, but no serial number.

	/usr/bin/hal-device |less		# on hudson, about 2000 lines of info.
}
(( 0 )) && {	# using "less" or "man", set a mark and, later, return to it.
	#
	# set a mark:		press "m" and then a letter.  (case sensitive)
	# return to mark:	press "'" and the letter.

	# run a command while in "less" or "man"
	#
	# exclaimation mark "!", type command
	# press "return" to return to less or man.
	echo
}
(( 0 )) && {	# netstat options
	# 
	# p	Show the PID and name of the program to which each socket belongs.
	# l	Show only listening sockets.
	# u	udp
	# t	tcp
	# n	numeric
	# a	Show both listening and non-listening sockets.
		With the --interfaces option, show interfaces that are not marked
	# s	Display summary statistics for each protocol.

	netstat -plutn

	options compare:
	-nap			343 lines.
	-nap |grep LISTEN	 44 lines.
	-nlp			 61 lines.
	-nlp |grep LISTEN	 44 lines.  Apparently no different than -nap |grep LISTEN
	-nlp |grep -v LISTEN	 17 lines.  all udp.
	-plutn			 28 lines.  tcp and udp.  looks useful!

}
(( 0 )) && {	# try these options with diff.

	diff --suppress-common-lines --side-by-side /etc/inittab{,.original}
	# prints: id:3:initdefault:                                             | id:5:initdefault:

	# how is the above different from this:		sdiff -s
	# from man sdiff: 
	#	sdiff without -o (or --output) produces a side-by-side difference.  This usage is obsolete; use diff --side-by-side instead
	#	-s  --suppress-common-lines  Do not print common lines.
	# So, ... don't use.
}
(( 0 )) && {	# Given a dir with several/many image files, identify duplicates.
	# Sort by size, then compare file1 vs file2, file2 vs file3, ...
	# If no diff, remove prev.

	DIR=/tmp/windowmovie
	PREV=''

	echo "  There are $(ls $DIR/*.xwd |wc -l) files in $DIR"

	for F in $(ls -S $DIR/*.xwd)
	do
		if [ -z $PREV ]
		then
			PREV=$F
			continue
		else
			echo "  Prev: $PREV   Curr: $F"
			DIFF=$(diff $PREV $F)
			[ -z "$DIFF" ] && echo "    rm: $PREV" && rm $PREV
			PREV=$F
		fi
	done
}
(( 0 )) && {	# Use diff Result Code.

	# An exit status of 0 means no differences were found, 
	# 1 means some differences were found, and 2 means trouble.

	diff ~/temp/iptable_notes{,_copy}
	EC=$?
	[ $EC -eq 2 ]  &&  echo -e "\tError code is 2, which means trouble."
	[ $EC -eq 1 ]  &&  echo -e "\tError code is 1, which means differences."
	[ $EC -eq 0 ]  &&  echo -e "\tError code is 0, which means no differences."

	[ $EC -ne 0 ]  &&  echo "\n\tThe files are different."

}
(( 0 )) && {	# diff versus cmp.  which is faster? 1.

	# compare tarballs on DVD vs harddisk

	dir1=/data/bu/diff/ja
	dir2=/data/bu/bu_users/ja
	echo -e "\tDir1: $dir1 \tDir2: $dir2"

	tarballs=$(find "$dir2" \( -iname '*.gz' -or -iname '*.tar' \)  \
		-type f -print |sed -e 's/\/data\/bu\/bu_users\/ja\///')
	# echo -e "\n\tTarballs: \n$tarballs"

	echo -e "\tCompare test 1: diff -- mainly for loading"
	time { for f in $tarballs; do echo -en "."; diff $dir1/$f $dir2/$f; done }; echo

	echo -e "\tCompare test 2: cmp"
	time { for f in $tarballs; do echo -en "."; cmp $dir1/$f $dir2/$f; done }; echo

	echo -e "\tCompare test 3: diff"
	time { for f in $tarballs; do echo -en "."; diff $dir1/$f $dir2/$f; done }; echo

	# results: on pacific:	6:41 vs 6:48; diff is 7sec faster, about 1sec/min, not sig.
	#		on q2:	9:55 vs 10:00; diff is 5sec faster, not sig.
	# So, ... use diff, forget cmp.
}
(( 0 )) && {	# diff versus cmp.  which is faster? 0.

	# compare tarballs on DVD vs harddisk

	dir1=/data/bu/diff/elh
	dir2=/data/bu/bu_users/elh
	echo -e "\tDir1: $dir1 \tDir2: $dir2"

	tarballs=$(find "$dir2" \( -iname '*.gz' -or -iname '*.tar' \)  \
		-type f -print |sed -e 's/\/data\/bu\/bu_users\/elh\///')
	# echo -e "\n\tTarballs: \n$tarballs"

	echo -e "\tCompare test 1: diff -- mainly for loading"
	time { for f in $tarballs; do echo -en "."; diff $dir1/$f $dir2/$f; done }; echo

	echo -e "\tCompare test 2: cmp"
	time { for f in $tarballs; do echo -en "."; cmp $dir1/$f $dir2/$f; done }; echo

	echo -e "\tCompare test 3: diff"
	time { for f in $tarballs; do echo -en "."; diff $dir1/$f $dir2/$f; done }; echo

	# results: on pacific:	cmp was 1:29 vs diff was 1:35
	#		on q2:	no sig difference
}
(( 0 )) && {	# list open files, lsof

	# /usr/sbin/lsof	# lists all open files belonging to all active processes
				# gives over 4000 open files on pacific
				# headings: COMMAND, PID, USER, FD, TYPE, DEVICE, SIZE NODE, NAME
				# FD=FileDescriptor.  see man lsof.

	lsof |egrep -i 'COMMAND|Deleted' |less		# list files that have been deleted (eg with rm) but the owning process has not yet finished.

	# /usr/sbin/lsof /bin/bash	# lists all processes that use bash
					# 6 files: bash, startx, firefox, run-mozil, bash, bash
	# /usr/sbin/lsof -p 40		# list open files for process with PID 40
					# lists 3 files: pdflush, pdflush, pdflush
	# /usr/sbin/lsof +D /tmp	# lists all open files in /tmp and its' subdirs, w/o symbolic links
					# lists 139 files on pacific

	# /usr/sbin/lsof -u ja		# list for specified user.  Over 2400 for ja
	# /usr/sbin/lsof -u ^root	# list for all users, except root.

	# /usr/sbin/lsof -d txt		# shows a process list, similar to ps aux, by listing entires
					# with the file descriptor entry of txt.
	# /usr/sbin/lsof -u ja +L	# shows link count for each file
	# /usr/sbin/lsof -u ja +L8	# shows files with link count less than 8
	# /usr/sbin/lsof +L1		# shows files that have been unlinked, ie: none.

	# /usr/sbin/lsof -i		# shows network-related files.  ~43.
	# /usr/sbin/lsof -i -P -n	# don't convert port number to port name, and don't resolve hostnames(for speed)
	# /usr/sbin/lsof -i |grep '\->'		# ESTABLISHED connections.
	# /usr/sbin/lsof -a -i -u ntp		# all open network files for the ntp account(AND relation -a)

	# /usr/sbin/lsof -t /dev/cdrom		# lists PIDs accessing cdrom.  Helpful when cannpt unmount CD.

	# /usr/sbin/lsof -i TCP -n -P \
	#	|awk '/LISTEN/ {print $1"/"$3"/"$8}'	# lists open ports, process names, user-names, interfaces.

	/usr/sbin/lsof -i TCP -n -P \
		|awk '/LISTEN/ {print $1"/"$3"/"$8}' \
		|sort -u				# same as above, and sort unique.

	# print the currently playing tune on baffin, under the elh login.
	/usr/sbin/lsof |grep elh |egrep '\.mp3$|\.ogg$' |awk '{print $9}'; echo

}
(( 0 )) && {	# rsync options:

	: <<-MYCOMMENTS

	-a			archive mode, equivalent to -rlptgoD
				(recursion and preserve almost everything.)
	-u			update only (don’t overwrite newer files)
	-v			verbose
	-e, --rsh=COMMAND	specify the remote shell, eg: -e ssh
	-P, --partial		keep partially transferred files
	-z, --compress		compress file data
	--progress		show progress during transfer.  (Very verbose.)
	--exclude <pattern>	exclude files matching some pattern, eg: "*~"
	--delete		delete files that don’t exist on sender
	-n, --dry-run		show what would have been transferred.
				Good to use with --delete "initially"

       -b, --backup		make backups (see --suffix & --backup-dir)
	   --backup-dir=DIR	make backups into hierarchy based in DIR.  good for incremental backups.
	   --suffix=SUFFIX	backup suffix (default ~ w/o --backup-dir)
 
	--delete --backup --backup-dir=$MIRROR_DIR/RsyncBckups --suffix=".$DATE"

	Allows you to keep an exact duplication of the original directory and
	keeping the original files that were either deleted or overwritten in
	a seperate backup directory with dated suffixes, which can be archived
	on some regular basis. 

	rsync -a				# for manual rsync within LAN.
	rsync -auv -e ssh --exclude <patt>	# for scripted rsync to 1and1 (to keep a log).

	MYCOMMENTS
}
(( 0 )) && {	# wrap with xargs -n

	echo "A B C D E F G H I J K L M N O P Q R S T U V W X Y" |xargs -n 5
}
(( 0 )) && {	# Problem with xargs.  features ?

	# On baffin: /usr/local/bin is not empty.  /usr/local/sbin is empty.

	for d in /usr/local/bin /usr/local/sbin
	do
		echo -e "\n\t========== $d "
		find $d -type f -print |xargs ls -al	# lists current dir if $d is empty
		EC=$? ; echo $EC			# prints: 0
	done

	# also shows:
	echo '' |xargs ls -al		# prints current dir.  
					# Just like "ls -al" would with no addnl parms.
}
(( 0 )) && {	# Get entries from the specified administrative database using the specified search keys.
	# Database is one of: aliases, ethers, group, hosts, netgroup, networks, 
	# passwd, protocols, rpc, services or shadow.

	# for db in aliases ethers group hosts netgroup networks passwd protocols rpc services shadow
	for db in passwd
	do
		echo -e "\tDatabase: $db"
		eval getent $db
		echo
	done
}
(( 0 )) && {	# bash test operators.  quoted variables.

	a=''
	[ -n "$a" ]  &&  echo "A is non-null"		# prints: 
	[ -z "$a" ]  &&  echo "A has a length of zero"	# prints: A has a length of zero
	echo "A: ***$a***"				# prints: A: ******

	[ -n "$b" ]  &&  echo "B is non-null"		# prints: 
	[ -z "$b" ]  &&  echo "B has a length of zero"	# prints: B has a length of zero
	echo "B: ***$b***"				# prints: B: ******

	c=$(cat /dev/null)
	[ -n "$c" ]  &&  echo "C is non-null"		# prints: 
	[ -z "$c" ]  &&  echo "C has a length of zero"	# prints: C has a length of zero
	echo "C: ***$c***"				# prints: C: ******

	# So, apparently, non-null is the opposite of length zero.  ie: -n = ! -z
}
(( 0 )) && {	# Get an average of some empirical value, eg: speed for a hard disk.
	# toss out the high and low readings, then average the rest.

	cum=0 ; high=0 ; low=999999999
	for i in {1..12}					# 12 samples.
	do
		speed=$(/sbin/hdparm -t /dev/mapper/VolGroup00-LogVol00 \
			|grep 'MB/sec' \
			|cut -d'=' -f2 \
			|sed -e 's/ MB\/sec//' \
			|sed -e 's/^\s*//')		# eg: 234.56 MB/sec --> 234.56

		cum=$( echo "$cum + $speed" |bc )	# use decimal math.

		[ $(echo "$speed > $high" |bc) -eq 1 ]  &&  high=$speed
		[ $(echo "$speed < $low"  |bc) -eq 1 ]  &&  low=$speed

		echo -e "\tI: $i \tSpeed: $speed \tCum: $cum "
	done
	echo -e "\tHigh: $high \tLow: $low "
	n=$(($i-2))					# use integer math.
	cum=$( echo "$cum - $high - $low" |bc )		# use decimal math.
	avg=$( echo "$cum / $n" |bc )
	echo -e "\tSummary: \tN: $n \tCum: $cum \tAvg: $avg "
}
(( 0 )) && {	# run a program some number of times.  accumulate totals.  round down to integers.
	# toss out the high and low numbers.

	cum=0 ; high=0 ; low=999999999
	for i in {1..12}
	do
		# get integer for speed in MB/sec.
		speed=$(/sbin/hdparm -t /dev/mapper/VolGroup00-LogVol00 \
			|grep 'MB/sec' \
			|cut -d'=' -f2 \
			|sed -e 's/ MB\/sec//' \
			|cut -d'.' -f1)

		cum=$(($cum + $speed))

		[ $speed -gt $high ]  &&  high=$speed
		[ $speed -lt $low  ]  &&  low=$speed

		echo -e "\tI: $i \tSpeed: $speed \tCum: $cum "
	done
	echo -e "\tHigh: $high \tLow: $low "
	n=$(($i-2))
	cum=$(($cum - $high -$low))
	avg=$(($cum / $n))
	echo -e "\tSummary: \tN: $n \tCum: $cum \tAvg: $avg "
}
(( 0 )) && {	# logical volume management.

	[ ! $(whoami) = 'root' ]  &&  echo "Must be root to execute."  &&  exit

	(
		/sbin/fdisk -l

		for c in dumpconfig formats segtypes \
			pvs pvscan pvdisplay \
			lvs lvscan lvdisplay lvmdiskscan \
			vgs vgscan vgdisplay vgck \
			version
		do
			echo -e "==================== /sbin/lvm $c \n"
			eval /sbin/lvm $c
			echo; echo; echo
		done
	) |less
}
(( 0 )) && {	# find all the executable files in a tree

	find ~ja/temp/spread/ -perm /u=x,g=x,o=x -type f 
}
(( 0 )) && {	# change DIR permissions to 755.

	# From: "nate" <[email protected]>
	# find <path> -type d -exec chmod 755 {} \;

	# Or, using -execdir
	find <path> -type d -execdir chmod 755 {} \;

	# From: Bill Campbell <[email protected]>
	find . -type d | xargs chmod 755

	# Or if the directories may have whitespace
	find . -type d -print0 | xargs -0 chmod 755
}
(( 0 )) && {	# Using "find" command when symbolic links are involved.

	# 3 "find" commands that are run on hudson.
	# find /home/ja/etc/config/ -iname '*startx*' -print |less
	# find /home/ja/etc/ -iname '*startx*' -print |less
	# find /home/ja/ -iname '*startx*' -print |less
	#
	# ### Of the 3 immediately above, the last does NOT work.
	# On fundy (where the etc dir really is) each of the 3 works.
	#
	# On hudson:
	# find /home/ja/ -ilname '*startx*' -print |less
	# find /home/ja/ -lname '*startx*' -print |less
	# find /home/ja/ -follow -iname '*startx*' -print |less
	#
	# ### Of the 3 immediately above, ONLY the last WILL work.
	echo "So, use -follow for symbolic links"
}
(( 0 )) && {	# Using "find" with multiple values for some parms.

	# multiple dirs.
	# find ~/public/1and1/fam/2006/pool_{leak,pad} -iname '*.php' -type f

	# multiple iname
	# find . \( -iname '*.wma' -or -iname '*.mp3' \) -type f -print 

	# files LT 5 days old and GT 0 days old.
	# find ~/temp  -maxdepth 1 \( -mtime -5 -and -mtime +0 \) -print	# Gets 3 files.

	# files LT 5 days old and GT 1 days old.
	# find ~/temp  -maxdepth 1 \( -mtime -5 -and -mtime +1 \) -print	# Gets 1 file.

	# files LT 5 days old and GT 2 days old.
	find ~/temp  -maxdepth 1 \( -mtime -5 -and -mtime +2 \) -print		# Gets 0 files, which is right.

}
(( 0 )) && {	# calendar mx

	# list the summary line from AE.  then compare with ...
	grep SUMMARY 2009-03-28_AE.ics |sed -e 's;^........;;' |sort

	# generate an AE only list.
	~ja/bin/ical_vevents.pl ./2009-03-28_AE.ics > agenda_test_ae

	# then get a "summary" list, to compare against AE.ics
	tail -n 47 ./agenda_test_ae |sed -e 's;^.*all-day....;;' |sort

	# look for 'old' dates in AE
	grep ^DTSTART 2009-03-28_AE.ics |grep DATE |grep -v ':2010' |sort

}
(( 0 )) && {	# find and mtime

	find ~/temp/calendars/google  -mtime -2 -print	# Gets files for today and yesterday,
							# ie, less than 2 days old.
	echo one
	find ~/temp/calendars/google  -mtime -1 -print	# Gets files for today,
							# ie, less than 1 days old.
	echo two
	find ~/temp/calendars/google  -mtime -0 -print	# Gets NO files
							# ie, less than 0 day old.
	echo three
	find ~/temp/calendars/google  -mtime +2 -print	# Gets one older file
							# ie, more than 2 days old.
	echo four
	find ~/temp/calendars/google  -mtime +1 -print	# Gets one older file
							# ie, more than 1 days old.
	echo five
	find ~/temp/calendars/google  -mtime +0 -print	# gets files for yesterday and older,
							# ie, more than 0 days old.
	# I guess that today is day 0, yesterday is day 1, ...
}
(( 0 )) && {	# print var name, var value.  must dereference var.  see ABS example 23-5
	# todo.  modify for null values: x=$(eval "expr \"\$$v\"")

	a=aaa; b=bbb; c=ccc; d=ddd

	for var in a b c d
	do
		# y=\$"$var" ;	x=$(eval "expr \"$y\" ")	# works.
		# y=\$"$var" ;	x=$(eval "expr $y ")		# works.
		# y=\$"$var" ;  x=$(eval "expr $y")		# works.
		# x=$(eval "expr \$${var}")			# works.
		# printf "\t%6s: %s \n" "$var" "$x"

		printf "\t%6s: %s \n" "$var" "$(eval "expr \$${var}")"		# works.

		# printf "\t%6s: %s \n" "$var" "$(eval "expr $${var}")"		# NO works.
		# printf "\t%6s: %s \n" "$var" "$(echo "expr \$${var}")"	# NO works.
		# printf "\t%6s: %s \n" "$var" "$(expr \$${var})"		# NO works.
	done
}
(( 0 )) && {	# use printf with a variable in the format statement, eg printf " %${NUM}s \n" "$SomeText"

	NUM=20 ; My1="  Begin. %-${NUM}s End. \n"

	printf "  Begin. %${NUM}s End. \n" "This is some text."		# prints: "  Begin.   This is some text. End."
	printf "  Begin. %-${NUM}s End. \n" "This is some text."	# prints: "  Begin. This is some text.   End."
	printf "${My1}" "This is some text."				# prints: "  Begin. This is some text.   End." 
	printf "${My1}" "This is more text."				# prints: "  Begin. This is more text.   End."

	# I guess "eval" is not needed.
}
(( 0 )) && {	# $1 might be a dir, filename, ..., that we want to check for unwanted characters.

	HERE=$1

	i=0
	i=$(($i+`echo "$HERE" | grep -c \ `))
	i=$(($i+`echo "$HERE" | grep -c \*`))
	i=$(($i+`echo "$HERE" | grep -c \\\\\\\\`))
	i=$(($i+`echo "$HERE" | grep -c \"`))
	i=$(($i+`echo "$HERE" | grep -c \'`))
	i=$(($i+`echo "$HERE" | grep -c \\\``))

	if [ $i -ne 0 ];
	then echo "Badness"
	else echo "Goodness"
	fi
}
(( 0 )) && {	# recent changes in ACC178

	echo -e "\n\tChanges in ACC178 in recent weeks. \n"

	for w in {1..12}						# weeks 1-x
	do 
		d=$((7*${w}))					# convert weeks to days.
		printf "\tChanged in the last %2d weeks: " "$w"
		find ~/public/1and1/acc -mtime -$d |wc -l	# count of changes
		find ~/public/1and1/acc -mtime -$d		# actual changes.
		echo
	done
}
(( 0 )) && {	# Find average file size, excluding home.  then for home

	for d in home data
	do
		c=$(find /$d |wc -l)
		printf "%15s: %12d\n" "$d" $c
		cum=$((cum+c))
	done
	printf "%15s: %12d\n" "Cum" $cum

	#  home:        72292
	#  data:         1245
	#   Cum:        73537

	# So, about 225 + 74 ~= 300,000 files
	# ~32GB used, ===> ~107 KB
}
(( 0 )) && {	# parse on word boundaries
	# ie, in /etc/services, look for port 25, but not 525 or 1525

	grep '\b25/' /etc/services	# \b matches the leading boundary.
					# / matches the following character.

	# alternately:
	grep -w 25 /etc/services	# -w means match words, with non-word boundary.
}
(( 0 )) && {	# Find "bin" dirs.  Ignore 5 trees

	BinDirs=$(find / \
		-path '/data' -prune -o \
		-path '/home/ja' -prune -o \
		-path '/mnt' -prune -o \
		-path '/NFS4exports' -prune -o \
		-path '/proc' -prune -o \
		-type d \
		-name '*bin' \
		-print)

	echo "  BinDirs:"
	echo $BinDirs
}
(( 0 )) && {	# use *find* but skip a few directories.

	# 1.  this works.
	find ~ja/temp \
		-path '/home/ja/temp/downloads' -prune -o \
		-path '/home/ja/temp/img' -prune -o \
		-path '/home/ja/temp/spread' -prune -o \
		-path '/home/ja/temp/calendars' -prune -o \
		-print |wc -l

	# 2.  also works.
	find ~ja/temp -path '/home/ja/temp/downloads'	-prune \
		-o -path '/home/ja/temp/img'		-prune \
		-o -path '/home/ja/temp/spread'		-prune \
		-o -path '/home/ja/temp/calendars'	-prune \
		-o -print \
		|wc -l

	# 3.  also works
	cd ~ja/temp
	find . -path './downloads'	-prune \
		-o -path './img'	-prune \
		-o -path './spread'	-prune \
		-o -path './calendars'	-prune \
		-o -print \
		| wc -l

	# 4.  does not yield the same as 3.  Yikes!
	cd ~ja/temp
	find . -path '/home/ja/temp/downloads'	-prune \
		-o -path './img'	-prune \
		-o -path './spread'	-prune \
		-o -path './calendars'	-prune \
		-o -print \
		| wc -l

	# 5.  yields same as 4.
	cd ~ja/temp
	find . -path '~ja/temp/downloads'	-prune \
		-o -path './img'	-prune \
		-o -path './spread'	-prune \
		-o -path './calendars'	-prune \
		-o -print \
		| wc -l


	# Apparently, the starting dir (~ja/temp), after expansion (/home/ja/temp) 
	# must be an exact text match of the -path value (/home/ja/temp), 
	# without reguard for actual location.

	# That is: starting dir (~ja/temp) gets expanded to /home/ja/temp
	# but path value (~ja/temp/downloads) does not get expanded, since it is in quotes.
	# Remove the quotes and it's prune logic is lost.

	# Good grief, can this be right?
}
(( 0 )) && {	# How to tell if your processor supports hardware kvm
	# from: http://kerneltrap.org/node/8088

	egrep '^flags.*(vmx|svm)' /proc/cpuinfo
}
(( 0 )) && {	# Get a collective time for a series of commands
	#
	# From: Luciano Miguel Ferreira Rocha <[email protected]>
	# On the [CentOS] mailing list

	cd ~ja/bin

	# what is the total time for running all 3 commands ??
	# using {}
	# time { tune.mgr.repos_compare; tune.mgr.filenames /data/mp3; tune.mgr.playlists /data/mp3; }

	# using ()
	# time ( tune.mgr.repos_compare.sh; tune.mgr.filenames /data/mp3; tune.mgr.playlists /data/mp3; )

	# Discussion on CentOS list: sometimes the time () approach does not work.
	# Better to use {} or sh -c approaches

	# using non-builtin time
	# /usr/bin/time sh -c "tune.mgr.repos_compare.sh; tune.mgr.filenames /data/mp3; tune.mgr.playlists /data/mp3;"

	# Reportedly, "time scriptname" will also work, provided that none of the 
	# commands in scriptname will fork to the background.
}
(( 0 )) && {	# Collect a series of screenshots.

	i=0
	while [ 1 ]
	do
		import -frame -window $1 "cap_$(printf "%04i" $i).miff" 
		i=$(( $i + 1 ))
		sleep 5
	done
}
(( 0 )) && {	# Screencast prep

	# take screenshot of named window.
	#
	import -frame -window 0xc00035 "test.miff"	# save in IM native format

	# convert miff to jpg
	#
	convert -antialias -resize 720x486! test.miff test.jpg

	# get the name of a window in X
	# run the xwininfo command and then click on a window.
	#
	xwininfo -frame |grep 'Window id:'	# prints: "xwininfo: Window id: 0xc00b0b (has no name)"
}
(( 0 )) && {	# wget options

	wget	--recursive \
		--no-clobber \
		--page-requisites \
		--html-extension \
		--convert-links \
		--restrict-file-names=windows \
		--domains website.org \
		--no-parent \
		www.website.org/tutorials/html/

	# This command downloads the Web site www.website.org/tutorials/html/.

	# The options are:
	#
	# --recursive: download the entire Web site.
	# --domains website.org: don't follow links outside website.org.
	# --no-parent: don't follow links outside the directory tutorials/html/.
	# --page-requisites: get all the elements that compose the page (images, CSS and so on).
	# --html-extension: save files with the .html extension.
	# --convert-links: convert links so that they work locally, off-line.
	# --restrict-file-names=windows: modify filenames so that they will work in Windows as well.
	# --no-clobber: don't overwrite any existing files (used in case the download is interrupted and resumed).
}
(( 0 )) && {	# go thru a list of URLs in a file, deleting each as it is used.
	# (after an interruption, we want to resume where we left off, not at begining.)

	T=~ja/temp/temp.$$

	cat > $T <<-ENDOFLIST;
		http://www.notbig.org
		http://www.cnn.com
		http://www.lugod.org
		http://www.linux.org
	ENDOFLIST

	while [ `find $T -size +0` ]
	do
		url=`head -n1 $T`
		# wget -c $url
		echo $url
		ERRORCODE=$?

		if [ $ERRORCODE -eq 0 ]
		then					# s="consider files as seperate", ...
			sed -si 1d $T			# i="edit files in-place", ...
		else					# 1d="line 1, delete" (I think.)
			echo "ERROR: could not get $url" 1>&2
			exit $ERRORCODE
		fi
	done
	rm $T
}
(( 0 )) && {	# list URLs in a file.

	f=~/temp/temp.ttt

	cat > $f <<-ENDOFLIST;
		http://www.notbig.org
		http://www.cnn.com
		http://www.lugod.org
		http://www.linux.org
	ENDOFLIST

	cat $f |xargs printf '\t%s\n'

}
(( 0 )) && {	# grab some lines from a list of proceses.  from unspawn on RKHunter list.  minor changes.

	RKHTMPVAR="" 

	# awk -F defines a string for field breaks.
	# ie, the string "syslogd -f somefile" will break on '-f'.

	for TMPVAR in `\ps -auwwx | grep syslogd | awk -F'-f' '{print $2}'`
	do
		if [ -f "$TMPVAR" ]
		then
			RKHTMPVAR=$TMPVAR
			break
		fi
	done 

	if [ -z $RKHTMPVAR ]
	then
		echo "Syslogd using regular configuration file."
	else
		echo "Syslogd using alternative configuration file: $RKHTMPVAR."
	fi
}
(( 0 )) && {	# Get config items re quick-launch tray for gnome-terminal.

	for X in /apps/panel/{general,objects/object_0}
	do
		echo -e "\n\t$X\n"
		/usr/bin/gconftool-2 --all-entries $X
	done > ~/temp/gnome-terminal-panel-config

	: <<-MYCOMMENTS

	/apps/panel/general

 profiles_migrated = false
 object_id_list = [menu_bar,object_0]
 enable_program_list = true
 enable_autocompletion = true
 show_program_list = false
 applet_id_list = [clock,systray,show_desktop_button,workspace_switcher,trash_applet,window_list]
 toplevel_id_list = [top_panel,bottom_panel]

	/apps/panel/objects/object_0

 toplevel_id = top_panel
 bonobo_iid = 
 attached_toplevel_id = 
 use_custom_icon = false
 action_type = lock
 tooltip = 
 custom_icon = 
 launcher_location = /usr/share/applications/gnome-terminal.desktop
 use_menu_path = false
 panel_right_stick = false
 object_type = launcher-object
 position = 325
 locked = false
 menu_path = applications:/

	MYCOMMENTS
}
(( 0 )) && {	# turn off system restart options at the login screen.

	gconftool-2 --direct --config-source xml:readwrite:/etc/gconf /gconf.xml.mandatory -t bool -s /apps/gdm/simple-greeter /disable_restart_buttons true
}
(( 0 )) && {	# change wallpaper to a random image every X seconds.  restore to original when done.

	seconds=4
	default=$(/usr/bin/gconftool-2 --get /desktop/gnome/background/picture_filename)

	declare -a images
	images=( $(ls ~ja/public/wallpaper/*.{png,jpg}) )
	count=${#images[@]}

	for x in {1..3}
	do
		i=$(($RANDOM%$count))		# starts with 0.
		img=${images[$i]}

		/usr/bin/gconftool-2 \
			--type "string" \
			--set /desktop/gnome/background/picture_filename $img
		sleep $seconds
	done

	/usr/bin/gconftool-2 \
		--type "string" \
		--set /desktop/gnome/background/picture_filename $default
}
(( 0 )) && {	# dump all entries, make config change, dump all entries, compare

	/usr/bin/gconftool-2 --all-entries /apps/
	/usr/bin/gconftool-2 --all-entries /desktop/

}
(( 0 )) && {	# play with the 'fold' command, to wrap text to a specified width.

	unit='Now is the time for all good men and women to come to the aid of their country.  ' # 81 characters.

	for x in `seq 1 9` ; do big="    $big $unit"; done		# 81 x 9 = 729 characters

	# echo $big |fold --spaces --width=50		# --spaces = break at spaces.
	# echo
	echo $big |fmt -w50			# some minor differences.
	echo
	# echo $big |fmt -w50 -u		# uniform spaces. 1 'tween words, 2 'tween sentences.  no diff.
	# echo $big |fmt -w50 -cu		# crown margin.  no diff.
	# echo $big |fmt -w50 -t		# tagged para.  no indent on first line.  else, indent 4 spaces.
	# echo $big |fmt -tuw50			# no diff.
}
(( 0 )) && {	# from maemo-users list.

	# [ja@pacific ~]$ cat /proc/sys/fs/file-nr	# from pacific.  file descriptor usage.
	# 2760    0       102655
	#
	# ~ $ cat /proc/sys/fs/file-nr			# from N800
	# 1059    0         4096

	: <<-MYCOMMENTS
	# from http://www.netadmintools.com/art295.html

	[root@srv-4 proc]# cat /proc/sys/fs/file-nr
	3391    969     52427
	|	 |       |
	|	 |       |
	|        |       maximum open file descriptors
	|        total free allocated file descriptors
	total allocated file descriptors
	(the number of file descriptors allocated since boot)
	MYCOMMENTS

	# ls /proc |wc -l				# 156 on pacific.  126 on N800

	for pid in /proc/[0-9]*
	do
		cmd=$(tr '\0' ' '<$pid/cmdline)
		if [ "$cmd" ]
		then
			#echo FDs for this pid: $(ls -l $pid/fd/|wc -l)
			#echo PID \(no path info\): ${pid##*/}
			#echo "base command: ${cmd%% *}"
			#echo "Nr FDs and basename: $(ls -l $pid/fd/|wc -l) ${cmd%% *}[${pid##*/}]"
			echo "$(ls -l $pid/fd/|wc -l) ${cmd%% *}[${pid##*/}]"
		fi
	done |sort -n
}
(( 0 )) && {	# from maemo user list.  "Let's add to the script output, 
	# also the (first crawler) process memory usage and 
	# check only files opened from the card(s):"

	# app=metalayer-crawler
	app=gmplayer					# get it running on "solo_guitars"

	# filter=media/
	filter=solo					# filter on "solo"

	# sleep=2
	sleep=10

	while true
	do
		pid=$(/sbin/pidof ${app} |cut -d' ' -f1);	# could manually get app name from ps aux
		ls -l /proc/${pid}/fd/ |grep $filter;		# what is happening right now?
		grep RSS /proc/${pid}/status;			# gets: VmRSS:     20140 kB
		echo -e "\tSleep for $sleep seconds"
		sleep $sleep
	done
}
(( 0 )) && {	# compare several approaches to parsing an apache logfile. 1.

	# From: Linux Mag.  Issue 64, March 2006

	# takes ~ 0.58 seconds, wall clock.
	# MUCH FASTER !!! than below.

	exec 3<~/temp/big_access_log		# uses file descriptor 3 to open the file
	while read -u 3 Request			# process one line at a time in the loop. no caching. ### double spaces.  wtfo.
	do
		Request="${Request##*GET }"	# remove from start-of-line thru GET
		echo "${Request%% HTTP/*}"	# remove from HTTP thru end-of-line
	done
}
(( 0 )) && {	# compare several approaches to parsing an apache logfile. 0.
	# From: Linux Mag.  Issue 64, March 2006

	# takes ~ 2.57 seconds, wall clock

	IFS=$'\n'
	for l in `cat ~/temp/big_access_log`	# reads whole file into memory before anything else.
	do 
		IFS=" "
		echo "${l}" | cut -d" " -f7	# calls "cut", an external program, for each loop
	done
}
(( 0 )) && {	# sort IP addresses.  

# From: http://linuxgazette.net/133/misc/lg/How_do_you_sort_an_IP_address_list.html

	f=~/t.$$

	cat > $f <<-ENDOFSORTLIST;
		10.123.189.105
		12.149.177.21
		12.154.4.213
		12.159.232.66
		12.205.7.190
		12.206.142.76
		12.214.50.126
		12.221.163.162
		12.30.72.162
		4.3.76.194
		8.10.33.176
	ENDOFSORTLIST

	# Use -t. to break the lines into fields on ., 
	# then sort 4 ints from left to right:
	# sort -t. +0n -1 +1n -2 +2n -3 +3n -4 < $f

	# sort -u -n -t. -k 1,1 -k 2,2 -k 3,3 -k 4,4 $f

	# Another way would be to multiply each address out into an int, sort, and re-format.
	#
	tr '.' ' ' < $f | xargs printf '%03d.%03d.%03d.%03d\n' |sort -u |sed -re 's/\b0+//g'
}
(( 0 )) && {	# regex patterns

	DICT=~/etc/config/dict/linux.words
	# egrep -i '^fu.*ia$' $DICT				# match whole lines

	for i in `seq 1 32`
	do
		echo "There are" `egrep '^.{'$i'}$' $DICT  \
			| wc -l` "$i-letter words in the dictionary."
	done
}
(( 0 )) && {	# Good Practices.  

# From: http://www-128.ibm.com/developerworks/aix/library/au-badunixhabits.html?ca=lnxw01GoodUnixHabits

	~ $ tar xvf -C tmp/a/b/c newarc.tar.gz		# unpack tarball into dir tmp/a/b/c
	~/tmp $ ls -1 | xargs file			# run "file" on each file in pwd.

	~/tmp $ ls -l | awk '$6 == "Dec"'		# match part of the date field
	# -rw-r--r--  3 joe joe   5096 Dec 14 14:26 archive.tar
	# -rw-r--r--  1 root root  238 Dec 03 08:19 README
}
(( 0 )) && {	# list current fonts

	for d in /usr/share/fonts/{bitmap-fonts,bitstream-vera,default,openoffice} \
		/usr/X11R6/lib/X11/fonts/{Type1,OTF} \
		~/.fonts
	do
		[ -d $d ]  &&  echo -e "\n\t$d"  &&  ls -l $d
	done
}
(( 0 )) && {	# update $vvp variable in *.php files.

	p=~/public/kin/fam/2006/au

	for f in $(ls ${p}/{mac,syd,tap}/*.php |grep -v index.php)
	do
		echo -e "\t${f}"
		cat ${f} |sed -e 's/zz\/lite/..\/zz\/lite/' >${f}.temp
		mv $f $f.old
		mv $f.temp $f
	done
}
(( 0 )) && {	# drivers

	f=/usr/share/hwdata/pci.ids		# list of PCI IDs in RHEL 4.4
	less $f					# has vendor number and name.
						# device number and name.  ...
						# see also: http://pciids.sourceforge.net/

	/sbin/lspci		# eg, 00:00.0 Host bridge: Silicon Integrated Systems [SiS] 645xx (rev 51)
	/sbin/lspci -n		# eg, 00:00.0 Class 0600: 1039:0648 (rev 51)
				# -n: Show PCI vendor and device codes as numbers.  Don't look up in PCI ID db.

	/sbin/modinfo ipw2100		# misc info. And aliases (cards to be handled by this module.)
					# udev will detect hardware, scan the modules list for a match, and load.
}
(( 0 )) && {	# Virtual Memory Statistics

	vmstat			# one-time
	vmstat -a 2 4		# 2 sec interval, 4 times.
	vmstat 1 20		# 1 sec interval, 20 times.  Use while Firefox loads.
}
(( 0 )) && {	# setup image date.  later, compare date with xml track info.

	show_3_times(){ ls -l --time=atime $1; ls -l --time=ctime $1; ls -l $1; echo; }

	IMG1=~ja/public/geo/geotag_images/jim.jpg
	show_3_times $IMG1

	# set mtime between 2006-09-02T14:47:01Z and 2006-09-02T14:47:07Z
	year=2006; month=09; day=02; hour=07; min=47; sec=03			# GMT -7 = PDT
	touch -m -t $year$month$day$hour$min.$sec $IMG1
	show_3_times $IMG1

	IMG2=~ja/public/geo/geotag_images/bfp.jpg
	show_3_times $IMG2

	# set mtime between 2006-09-02T14:51:52Z and 2006-09-02T14:51:57Z
	year=2006; month=09; day=02; hour=07; min=51; sec=55			# GMT -7 = PDT
	touch -m -t $year$month$day$hour$min.$sec $IMG2
	show_3_times $IMG2

}
(( 0 )) && {	# filter tracks.txt for gpsvisualizer input.  format: name,lat,long
	# use sequential number for name.
	# grep '<trkpt ' ./tracks.txt |sed -e 's/\" lon=\"/,/' -e 's/>//' -e 's/<trkpt lat="/b,/'

	i=0
	for s in $( grep '<trkpt ' ./tracks.txt |sed -e 's/\" lon=\"/,/' -e 's/>//' -e 's/<trkpt lat="//' )
	do
		((i++))
		echo "$i,$s"
	done
}
(( 0 )) && {	# download info from Garmin eTrex gps receiver.

	# verify /dev/ttyS0 is rw for all

	TTY=/dev/ttyS0
	[ $( ls -l $TTY |grep '^crw-rw-rw-' |wc -l ) -lt 1 ]  \
		&& echo -e "\tNot rw for all: $TTY \n\tAs root, chmod a+rw" \
		&& exit 1

	F=~/public/geo/geotag_images/waypoints.txt
	~/bin/gpsbabel  -igarmin -f $TTY -o gpx -F $F

	F=~/public/geo/geotag_images/tracks.txt
	~/bin/gpsbabel -t -igarmin -f $TTY -o gpx -F $F
}
(( 0 )) && {	# color screen characters.

tput clear			# clear the screen
tput cup 3 15			# Move cursor to screen location Row,Col (top left is 0,0)
tput setaf 3			# Set a foreground colour using ANSI escape
echo "XYX Corp LTD."
tput sgr0			# Reset text attributes w/o clearing screen.
tput cup 5 17

tput rev			# Set reverse video mode
echo "M A I N - M E N U"
tput sgr0			# Reset text attributes...
 
tput cup 7 15
echo "1. User Management"
 
tput cup 8 15
echo "2. Service Management"
 
tput cup 9 15
echo "3. Process Management"
 
tput cup 10 15
echo "4. Backup"

tput bold			# Set bold mode
tput cup 12 15
read -p "Enter your choice [1-4] " choice
 
tput clear
tput sgr0
tput rc

# Prints:
               XYX Corp LTD.

                 M A I N - M E N U

               1. User Management
               2. Service Management
               3. Process Management
               4. Backup

               Enter your choice [1-4] 
}
(( 0 )) && {	# color echo

	black='\E[30;47m'
	red='\E[31;47m'
	green='\E[32;47m'
	yellow='\E[33;47m'
	blue='\E[34;47m'
	magenta='\E[35;47m'
	cyan='\E[36;47m'
	white='\E[37;47m'

	cecho ()
	{
		local default_msg="No message passed."

		message=${1:-$default_msg}		# Default message.
		color=${2:-$black}			# Default color.

		echo -e "$color"
		echo "$message"
		tput sgr0				# Reset text attributes w/o clearing screen.

		return
	}  

	cecho "Feeling blue..." $blue
	cecho "Magenta looks more like purple." $magenta
	cecho "Green with envy." $green
	cecho "Seeing red?" $red
	cecho "Cyan, more familiarly known as aqua." $cyan
	cecho "No color passed (defaults to black)."		# no color passed.
	cecho "\"Empty\" color passed (defaults to black)." ""	# Empty $color argument.
	cecho							# Missing $message and $color arguments.
	cecho "" ""						# Empty $message and $color arguments.

	echo
}
(( 0 )) && {	# Prints a table of ASCII characters.
	# Sorta centers the values under the headings.

	START=33   # Range of printable ASCII characters (decimal).
	END=125

	printf "\t%7s  %3s  %8s \n" "Decimal" "Hex" "Character"
	printf "\t%7s  %3s  %8s \n" "-------" "---" "---------"

	for ((i=START; i<=END; i++))
	do
		echo $i | awk '{printf("\t%4d  %6x  %5c \n", $1, $1, $1)}'
	done
	exit 0
}
(( 0 )) && {	# debugging techniques.

	# Version 1.
	debug=1
	(( $debug ))  &&  echo -e "\tThis will print, since debug is set to 1."		# yep, it prints.

	debug=0
	(( $debug ))  &&  echo -e "\tThis will NOT print, since debug is set to 0."	# yep, it does NOT print.


	# Version 2.
	qaprint() { [ ! -z "$qa" ]  &&  echo -e "\t$1" >&2; }

	qa=1
	qaprint "Since qa is 1, this will print"		# yep, it prints.

	qa=
	qaprint "Since qa is null, this will NOT print"		# yep, it does NOT print.


}
(( 0 )) && {	# Delete contents of a file, but preserve the file itself, (and permissions)

	f=/home/ja/temp/TenGO/Palm5_Installation_Instructions.pdf
	[ -f $f ]  &&  cat /dev/null > $f

	f=/home/ja/temp/TenGO/TengoUserManual_Palm.pdf
	[ -f $f ]  &&  : > $f		# has same effect, but does not spawn a new process.

}
(( 0 )) && {	# alternate means to determine process for a given pid.

	echo Alt1
	find /proc/$1/exe -printf '%l\n'

	echo Alt2
	/usr/sbin/lsof -aFn -p $1 -d txt | sed -ne 's/^n//p'
}
(( 0 )) && {	# Get process path name for a given pid.
	# use an existing pid as $1

	[ $# -ne 1 ]  &&  echo "Usage: `basename $0` PID-number" >&2  &&  exit 1

	pidno=$( ps ax | grep $1 | awk '{ print $1 }' | grep $1 )

	[ -z "$pidno" ]  &&  echo "No such process running."  &&  exit 1

	PROCFILE=exe
	if [ ! -r "/proc/$1/$PROCFILE" ]
	then
		echo "Process $1 running, but..."
		echo "No read permission on /proc/$1/$PROCFILE."
		exit 1
	fi  

	exe_file=$( ls -l /proc/$1/exe | awk '{ print $11 }' )

	if [ -e "$exe_file" ]
	then echo -e "\tProcess #$1 invoked by $exe_file."
	else echo -e "\tNo such process running."
	fi
}
(( 0 )) && {	#  Starting the script with "#!/bin/bash -r" runs entire script in restricted mode.

	echo -e "\tChanging directory."
	cd /usr/local
	echo -e "\tNow in `pwd`"
	echo -e "\tComing back home."
	cd
	echo -e "\tNow in `pwd` \n"

	# Everything up to here in normal, unrestricted mode.

	set -r				# set --restricted    has same effect.
	echo -e "\t==> Now in restricted mode. <=="
	echo -e "\n\n\tAttempting directory change in restricted mode."
	cd ..
	echo -e "\tStill in `pwd`"

	# echo -e "\n\n\t\$SHELL = $SHELL"
	# echo -e "\tAttempting to change shell in restricted mode."
	# SHELL="/bin/ash"		# does not permit this.  aborts script.
	# echo -e "\n\t\$SHELL= $SHELL"

	echo -e "\n\n\tAttempting to redirect output in restricted mode."
	ls -l /usr/bin > bin.files
	ls -l bin.files    # Try to list attempted file creation effort.
}
(( 0 )) && {	# avoid subshell problem.

	fn=~ja/temp/temp.$$
	cat <<- EOF >> $fn
		Line 1.
		Line 2.
		Line 3.
		Line 4.
		Line 5.
	EOF

	Lines=0
	cat $fn | while read line		# ?? pipe creates subshell ??
	do
		echo $line ; (( Lines++ ))
	done
	echo "Number of lines read = $Lines"	# prints 0	# Wrong!

	Lines=0
	while read line				# redirect file to while loop
	do
		echo $line ; (( Lines++ ))
	done < $fn
	echo "Number of lines read = $Lines"	# prints 5	# Right!

	Lines=0
	exec 3<> $fn				# Assign filehandle 3 to $fn
	while read line <&3
	do
		echo "$line" ; (( Lines++ ))
	done
	exec 3>&-
	echo "Number of lines read = $Lines"	# prints 5	# Right!

	rm $fn
}
(( 0 )) && {	# comment out code, on a temp basis.

	echo -e "The code below will not print."

	: <<-DEBUGXXX
	for file in *
	do
		cat "$file"
	done
	DEBUGXXX

	echo -e "Note the \"-\" just prior to DEBUGXXX."
}
(( 0 )) && {	# Using the m4 macro processor.
	# m4 builtin functions: len, substr, regexp, incr, eval, ...

	# Strings
	string=abcdA01
	echo "len($string)" | m4			# 7
	echo "substr($string,4)" | m4			# A01 (first char is position zero.)
	echo "regexp($string,[0-1][0-1],\&Z)" | m4	# 01Z

	# Arithmetic
	echo "incr(22)" | m4				# 23
	echo "eval(99 / 3)" | m4			# 33
}
(( 0 )) && {	# graphic of "tee" command

	#                           |----> redirect to file
	#                           |
	# ==========================|====================
	# command ---> command ---> |tee ---> command ---> ---> output of pipe
	# ===============================================

	cat ~/temp/curl_options | sort | tee curl.check | uniq > curl.result
}
(( 0 )) && {	# more play with bc. 1.
	# using files.

	f=~/t.$$

	cat > $f <<-ENDOFBCCODE;
		scale=2

		/* C-style comments
		   are allowed, as are spaces */

		print "\nConvert Fahrenheit to Celsius\n\n"
		print "Temperature in Fahrenheit: " ; fah = read()
		print "\n"
		print "Equivalent Temperature in Celsius is: "
		(fah - 32.0) * 5.0 / 9.0
		quit
	ENDOFBCCODE

	# to envoke:	$ bc -q $f
}
(( 0 )) && {	# more play with bc. 0.
	# thanks: http://www.basicallytech.com/blog/index.php?/archives/23-command-line-calculations-using-bc.html

	echo '57+43' | bc		# 100
	echo '57-43' | bc		# 14
	echo '57*43' | bc		# 2451
	echo 'scale=25;57/43' | bc	# 1.3255813953488372093023255
	echo 'scale=30;sqrt(2)' | bc	# 1.414213562373095048801688724209
	echo '6^6' | bc			# 46656
	echo '(6^6)^6' | bc		# 10314424798490535546171949056

	echo 'obase=16;255' | bc		# FF	# convert 255 from base 10 to base 16.
	echo 'obase=2;12' | bc			# 1100	# convert  12 from base 10 to base 2.
	echo 'ibase=2;obase=A;10' | bc		# 2	# convert from binary to deciaml
	echo 'ibase=2;obase=A;10000001' | bc	# 129	# 
	echo 'ibase=16;obase=A;FF' | bc		# 255	# convert from hex to decimal.

	FIVE=5 ; echo "$FIVE^2" | bc	# 25	# using bc in shell scripts.
}
(( 0 )) && {	# add column headings.  format columns.

	# "column" uses logical columns.
	(printf "PERMISSIONS LINKS OWNER GROUP SIZE MONTH DAY HH:MM PROG-NAME\n"; \
		ls -l /usr/local/bin/pilot*) | column -t

	# colrm uses character columns.  (better know the format of input text!)
	(printf "PERMISSIONS LINKS OWNER GROUP SIZE MONTH DAY HH:MM PROG-NAME\n"; \
		ls -l /usr/local/bin/pilot*) | column -t |colrm 14 60

}
(( 0 )) && {	# downshift: this function return the argument as downshifted string
	# from: http://www.samag.com/documents/s=9373/sam0203f/0203f.htm

	function down_shift
	{
		# alternate translate command
		# echo $1 | tr "[:upper:]" "[:lower:]"

		echo $1 | tr '[A-Z]' '[a-z]'
	}

	string="ALLLOWERCASE"
	string=$(down_shift $string)
	printf "%s\n" $string
}
(( 0 )) && {	# path munging, from /etc/profile

	# Note interesting pattern matching with egrep.  From the man page:
	#	Repetition takes precedence over concatenation,
	#	which in turn takes precedence over alternation.  
	#	A whole sub-expression may be enclosed in parentheses to override these precedence rules.

	ppath='a:b:c:d:e'		# psuedo path
	pathm() 
	{
		# If $1 is already in ppath, then do nothing.
		# If not in path, then add before or after.

		if ! $(echo $ppath | /bin/egrep -q "(^|:)$1($|:)")
		then
			if [ "$2" = "after" ];	then ppath=$ppath:$1
			else			ppath=$1:$ppath
			fi
		fi
	}
	pathm c;			echo -e "\tPpath: $ppath";	# no change.
	pathm /usr/local/sbin;		echo -e "\tPpath: $ppath";	# adds $1 to begin of ppath.
	pathm /usr/X11R6/bin after;	echo -e "\tPpath: $ppath";	# adds $1 to end of ppath.
}
(( 0 )) && {	# build a string of items.  special handeling for first item.

	dm=
	for d in /usr/man /usr/share/man
	do
		if [ -d $d ]
		then
			if [ x$dm = x ]
			then 
				dm=$d; else dm=$dm:$d
			fi
		fi
	done
	echo "dm: $dm"
}
(( 0 )) && {	# play with using "find" then looking at each file.

	find ~ja/public/web/ideas/ -iname '*.html' -type f \
		|xargs grep '\.css' \
		|grep -v 'strict.dtd'
}
(( 0 )) && {	# wtf re errors from /etc/cron.weekly/00-makewhatis
	# ?? incorrect format of NAME in man pages ??

	# later, use output of $(man --path)
	# for d in /usr/kerberos/man
	# for d in /usr/local/share/man
	# for d in /usr/share/man/en
	# for d in /usr/share/man
	for d in /usr/share/man/man{0p,1,1p}
	# for d in /usr/X11R6/man/man1
	do
		[ ! -d $d ]  &&  echo -e "NOT a dir: $d"  &&  exit
		echo -e "\tDir: $d"
		find $d -iname '*.gz' -type f -execdir /home/ja/bin/manpage_name.sh '{}' \;
		echo
	done

}
(( 0 )) && {	# play with ~ja/temp/nvram-clean.sh and /root/nvram-show
	# just look at "type"

	echo -e "\n===== 15 Most Frequent key _TAILS_ ====="
	cat /root/nvram-show 2>/dev/null | \
	{
		while read LINE				### double spaces probably naf.
		do
			CONTENTS="${LINE##*=}"		# del longest match from LEFT. gives value.
			LINE="${LINE%%=*}"		# del longest match from RIGHT. gives key.
			TYPE="${LINE%%_*}"		# del longest match from RIGHT. gives left of _
			TAIL=${LINE##*_}		# gives right of _.  ie, the key tail.
			echo "$TAIL"
		done
	} |sort |uniq -c |sort -rn |head -n 15
}
(( 0 )) && {	# get a list of subfolders sorted by their size

	du -k --max-depth=1 /temp/ | sort -n -r

	# or, to avoid crossing into another filesystem
	du -xk --max-depth=1 / |sort -rn

	# or, find recent large files
	find . -mount -ctime -1 -size +5M	# files within the last day, with size GT 5MB.

	# or, print out size directly
	find . -mount -ctime -1 -size +5M -printf "%k %p\n"	# k=KB p=filename

}
(( 0 )) && {	# Some X notes

	xset q			# shows current settings
}
(( 0 )) && {	# list shared memory processes with ipcs, extract the cpid (creator pid ??), 
	# then find each pid is the output of ps.
	# Thanks to [email protected], msg author: dking@ketralnis

	# filter out verbiage in ipcs output using egrep.  also, sort and remove dups.
	ipcs -pm |cut -c23-26 |egrep ^[0-9] |sort -n |uniq \
		|while read r; do ps auxww |grep $r |grep -v 'grep'; done		### double spaces probably naf.

	# use perl rather than egrep.
	# ipcs -pm |cut -c23-26 |perl -n -e 'print if /^\d/' |sort -n |uniq \
	#	|while read r; do ps auxww |grep $r |grep -v 'grep'; done		### double spaces probably naf.
}
(( 0 )) && {	# use grep to match *just* the pattern, not the whole line.

	# snap the urls from a logfile.  then sort, count, sort numberic, and take top few.

	# egrep -o '(((http(s)?)://)[^/]+)' \
	#	~/bin/support/check_access/check_access.log \
	#	|sort |uniq -c |sort -nr |head -n 4

	# grep is smart enough to avoid passing color to a pipe.  
	# but, it can be forced.
	egrep --color=always -o '(((http(s)?)://)[^/]+)' \
		~/bin/support/check_access/check_access.log \
		|sort |uniq -c |sort -nr |head -n 4
}
(( 0 )) && {	# some ps one-liners

	ps -eo user,pcpu,pid,cmd | sort -r -k2 | head -6	# show processes in cpu % order.
	ps -eo pcpu,user,pid,cmd | sort -r | head -6		# show processes in cpu % order.
}
(( 0 )) && {	# this is a list of ps options from elsewhere in this file.  Plus a little more.
	# ToDo: sort thru and summarize.  Make it easy to decide which to use.

	ps aux			# 11 columns, as root or ja.
	ps auxw			# no difference.
	ps auxww		# no difference.
	ps ax			# 5 cols, as ja or root.
	ps -f		# see which processes are attached to the tty.  Use with an ssh session to prevent hangs.

	ps xaf			# tree-like, 5 cols: PID TTY STAT TIME COMMAND
        ps -eo pid,state,nice,args
        ps -e						# all processes.  4 columns: PID TTY TIME CMD
        ps -eo pid:10,time,command			# works.
        ps -eO rss					# 6 cols: PID RSS S TTY TIME COMMAND
        ps -eo pid,rss,state,tname,time,command			# save as above
        ps -eo pid,rss,vsz,time,command				# 5 cols.
        ps -eo pid,rss=ResidentSetSize,vsz,time,command		# same as above.
        ps -eo pid,rss:15,vsz,time,command			# same as above.
        ps -eo user:15,pid,ppid,c,stime,tname,time,cmd
        ps -eo pid,ppid,%cpu,%mem,time,cmd:80			# did NOT limit col width.  ???
        ps -eo pid,ppid,%cpu,%mem,time,comm			# just the command, no parms.
        ps -eo pid,ppid,%cpu,%mem,time,nice=Nice,rss=ResidentSetSize,comm
        ps -A							# all processes owned by user
        ps -A -o rss,vsz,command| grep bash
}
(( 0 )) && {	# Simple process selection options:
	echo
# -A	Select all processes (SAP). Identical to -e.
# -N	SAP except those that fulfill the specified conditions.
#  T	SAP associated with this terminal. Identical to the t option without any argument.
# -a	SAP except session leaders (see getsid(2)) and processes not associated with a terminal.
#  a	List all processes with a terminal (tty), or when used together with the x option.
# -d	SAP except session leaders.
# -e	SAP. Identical to -A.
#  r	Restrict the selection to only running processes.
#  x	List all processes owned by you (same EUID as ps), or when used together with the a option.
# -w	wide output.  Use twice for unlimited width.
}
(( 0 )) && {	# process status, including nice.
	#	-e		all precesses (everything)
	#	-A		All precesses (everything)
	#	-o Format	user defined format
	# ps -eo pid,state,nice,args | less

	# filter out most of the nice=0 lines.
	ps -eo pid,state,nice,args \
		|grep -v '0 \[' \
		|grep -v '0 \/' \
		|grep -v '0 g' \
		|grep -v '0 bash' \
		|less
}
(( 0 )) && {	# various formats for ps.

	# ps -e						# all processes.  4 columns: PID TTY TIME CMD

	# ps -eo pid=ProcessID,time,command		# does not work.
	# ps -eo pid:10,time,command			# works.

	# ps -eO rss					# 6 cols: PID RSS S TTY TIME COMMAND
	# ps -eo pid,rss,state,tname,time,command	# save as above

	# ps -eo pid,rss,vsz,time,command			# 5 cols.
	# ps -eo pid,rss=ResidentSetSize,vsz,time,command	# same as above.
	# ps -eo pid,rss:15,vsz,time,command			# same as above.

	# ps -eo user:15,pid,ppid,c,stime,tname,time,cmd

	# ps -eo pid,ppid,%cpu,%mem,time,cmd:80		# did NOT limit col width.  ???
	# ps -eo pid,ppid,%cpu,%mem,time,comm		# just the command, no parms.

	ps -eo pid,ppid,%cpu,%mem,time,nice=Nice,rss=ResidentSetSize,comm
}
(( 0 )) && {	# process status, ps
	# rss and vsz are in KB.

	# ps -A		# all processes owned by user

	# list 3 columns for all bash processes
	# ps -A -o rss,vsz,command| grep bash	

	# total the columns for rss and vsz.
	ps -A -o rss,vsz,command| grep bash \
		|awk '{rss += $1; vsz += $2 } END { print "Real: ",rss, "Virtual: ",vsz }'
}
(( 0 )) && {	# ack uses perl's regex at the cli.
	# Find all the modules used in a source tree.  ie: use Module::Name::Text qw/ blah blah /;

	ack -h '^use\s+(\w+(?:::\w+)*).*' <SomeTree> --output=\$1 | sort -u

	# ja notes: use Module::Name::Text qw/ abcd efgh /;
	#               ------					( first \w+ match )
	#                     ------				( first  ?:::\w+ match )
	#			    ------			( second ?:::\w+ match )
	#                                 -----------------	( the .* match )
	#               ------------------			( $1 )
	#
	# run against ~ja/bin.  probably do NOT need ~/public/lang/perl.
}
(( 0 )) && {	# CPAN module installs.

	# From: Gavin Carr <[email protected]>
	# Subject: Re: [CentOS] Enbended Perl
	# To: CentOS mailing list <[email protected]>
	# [...]
	# It's a cpan module called Embperl. You can either install it straight from cpan:

	perl -MCPAN -e 'install Embperl'	# enters endless dialog.  ?? config file ??

	# or look at using something like cpan2rpm (http://perl.arix.com/cpan2rpm/)

}
(( 0 )) && {	# perl at the cli.  print lines that match a pattern.  then filter out unwanted.

	# in this specific case, look for the letter j, i, and m, with interveening characters,
	# filter out 'ism'.

	perl -ne 'print if /.*j.*i.*m/i' ~/etc/config/dict/linux.words \
		|grep -iv 'ji' |grep -iv 'im' |grep -iv 'ism' |less

	# a code listing has line numbers like <spaces>=n=<spaces> before each line.
	# lines 1-9 have 5 spaces after the line number.  10-99 have 4 spaces.  100-999 have 3 spaces.
	# remove the line numbers and spaces.

	perl -n -e 's/^\s*=\d=\s{5}//; print' find_similar_images.pl \
		| perl -n -e 's/^\s*=\d\d=\s{4}//; print' \
		| perl -n -e 's/^\s*=\d\d\d=\s{3}//; print' \
		| less
}
(( 0 )) && {	# more perl at the cli. Randal L. Schwartz, 2006.11.02. www.samag.com

	f='/home/ja/temp/emedicine_image_hack';

	# For text processing, we can add -n, which puts a wrapper around our program that looks like:
	# LINE:
	#  while (<>) {
	#    ... # rest of your program here
	#  }

	# eg, print each line with a sequential line number in front. Use the $. variable for the numbers:
	# perl -n -e 'print "$.: $_"' $f

	# Another way to approach this problem is the -p, which adds a print at the end of the loop:
	# LINE:
	#   while (<>) {
	#     ... # your program here
	#     print;
	#   }

	# So, we could just substitute the line number into the beginning of each line:
	perl -pe 's/^/$.: /' $f
}
(( 0 )) && {	# perl cli.  count all occurances of a string, eg, jerry.

	# 
	echo "jerry jerry" | perl -lane '$count = grep $_ =~ m/jerry/, @F; print $count'

	# From: "Ross S. W. Walker" <[email protected]>
	echo "jerry jerry" | awk 'BEGIN{RS=FS} /^jerry$/ {jerry++} END{print jerry}'

	# From: Stephen Harris <[email protected]>
	echo "jerry jerry" | tr -c '[:alnum:]' '\012' | grep -c jerry

}
(( 0 )) && {	# perl at cli.  http://programming.newsforge.com/article.pl?sid=06/03/08/1456241&from=rss
	# thanks: Hubert Chen
	# (see more examples later in this file.)
	#
	# perl cli options: 
	#	-p = "print" lines. assume input loop.
	#	0777 = "slurp" in whole file at once.
	#	00 = read files in "paragraph mode"; equivalent to undefining the $/ variable, ie INPUT_RECORD_SEPARATOR
	#	-i = "in-place" file edits.
	#	-e = "execute" this perl command.
	#	-n = "no-print".  assume input loop.
	#	-a = "autosplit" each line.  saves fields to @F
	#	-l = auto "line" ending processing.
	#	-F = "Field" delimiter. (default is space char, ie, " ")

	file=/home/ja/temp/FC5_notes

	# Edit the file in place and make a backup of the old version as well.
	# perl -pe 's/mp3/MP3/g' < $file > $file.new

	# make a backup with -i.old, then do in-place replacement.
	# perl -p -i.old -e 's/mp3/MP3/g' $file

	# do a bunch of files.
	# perl -p -i.old -e 's/oldstring/newstring/g' myfiles*

	# change all the strings in all files recursively:
	# find . | xargs perl -p -i.old -e 's/oldstring/newstring/g'

	# print the fourth word of every line, but also skip any line beginning with a #.
	# perl -naF -e 'next if /^#/; print "$F[3]\n"' < $file

	# extract all usernames from /etc/passwd.
	# perl -na -F: -e 'print "$F[0]\n"' < /etc/passwd

	# or: -F/:/
	# To split on whitespace use -F'/\s+/'.

	# from the comments section:

	# Pick a random file (e.g. MP3)
	# ls /home/ja/temp | perl -e '@a=<>;print $a[rand(@a)]'

	# Shuffle the contents of a file
	# cat $file |perl -e '@a=<>;while(@a){print splice(@a,rand(@a),1)}' |less
}
(( 0 )) && {	# perl cli, pattern matching.

	# Thanks Ben Browning, http://www.linux.com/article.pl?sid=06/01/17/2036214

	# cat /etc/passwd | perl -ne 'print if $_=~/daemon/'	
		# print line in passwd, if matches daemon
		# prints: daemon:x:2:2:daemon:/sbin:/sbin/nologin
		# and:    haldaemon:x:68:68:HAL daemon:/:/sbin/nologin
	# from LWN comment at: http://lwn.net/Articles/169495/
	perl -ne 'print if /daemon/' /etc/passwd		# prints the same as above
}
(( 0 )) && {	# perl at the cli.  http://www.redhat.com/magazine/005mar05/features/perl/
	# thanks: Chip Turner
	#
	# perl cli options: 
	#	-p = "print" lines. assume input loop.
	#	-i = "in-place" file edits.
	#	-e = "execute" this perl command.
	#	-n = "no-print".  assume input loop.
	#	-a = "autosplit" each line.  saves fields to @F
	#	-l = auto "line" ending processing.
	#	-F = "Field" delimiter. (default is space char, ie, " ")

	# seq 1 10 | perl -p -e '$_ = "prefix: $_"'	# add a prefix to each variable
	# perl -p -e 's/:.*//' /etc/passwd		# all system users.

	# perl -n -e '@fields = split /:/; print "$fields[0]\n"' /etc/passwd	# all sysem users, again. 1/line.
	# perl -n -e '@fields = split /:/; chomp @fields; print "$fields[0], ";' /etc/passwd	# comma seperated.

	# perl -l -a -n -e 'print $F[6]' ~/temp/access_log	# list of URLs requested. 1/line
	# perl    -a -n -e 'print $F[6]' ~/temp/access_log	# list of URLs requested. mushed together.
	# perl    -a -n -e 'print "$F[6], "' ~/temp/access_log	# list of URLs requested. sep by ", ".

	# what are teh most requested files?
	# cat ~/temp/access_log | perl -l -a -n -e 'print $F[6]' | sort | uniq -c | sort -n | tail -n 10

	# who is hitting the server the most?
	# cat ~/temp/access_log | perl -l -a -n -e 'print $F[0]' | sort | uniq -c | sort -n | tail -n 10

	# make in-place changes to a large number of files.
	# find -type f -name '*.txt' | xargs perl -p -i -e 's/PLACEHOLDER/new_value/g'

	# perl -F: -l -a -n -e 'print $F[0]' /etc/passwd		# all system users. using -F. 1/line.
	# perl -F:    -a -n -e 'print "$F[0], "' /etc/passwd; echo	# all system users. sep by ", "

	# cat ~/temp/access_log | perl -l -a -n -e '$n += $F[9]; } END { print $n'	# total bytes server.

	# convert unix timestamps to human-readable form.
	# echo "1104903117 0.3" | perl -l -a -n -e 'print scalar(localtime $F[0]), " @F[1..$#F]"'

	echo "1104903117 0.3" >	 ~ja/temp/wierd-timestamp	# Tue Jan  4 21:31:57 2005
	echo "1104903177 0.4" >> ~ja/temp/wierd-timestamp	# plus 60
	echo "1104906717 0.5" >> ~ja/temp/wierd-timestamp	# plus 3600
	# cat ~ja/temp/wierd-timestamp | perl -l -a -n -e 'print scalar(localtime $F[0]), " @F[1..$#F]"' # ver 1
	# cat ~ja/temp/wierd-timestamp | perl -l -a -n -e '$F[0] = scalar localtime $F[0]; print "@F"'   # ver 2

#	Perl at the command line:
#
#	Reverse parts of a web address.  
#	eg, www.whatever.com --> whatever.www.com
#	or, ftp.whatever.org --> whatever.ftp.org
#	perl -i.bak -p -e 's/(www|ftp)\.(.*?)\.(com|gov)/$2.$1.$3/gi' resources.php
#
}
(( 0 )) && {	# Start with "tolkien".  using only these letters, find words in /usr/share/dict/linux.words
	# Thanks: http://perlbuzz.com/mechanix/2008/06/scrabble-cheating-with-perl-on.html

	perl -lne' print if /t/ && /o/ && /l/ && /k/ && /i/ && /e/ && /n/' /usr/share/dict/words |wc -l				# prints: 294

	perl -lne' print if /t/ && /o/ && /l/ && /k/ && /i/ && /e/ && /n/ && length($_)==8' /usr/share/dict/words		# prints: knotlike, konilite, townlike
	# There were no words of 7 characters or less

	perl -lne' print if /t/ && /o/ && /l/ && /k/ && /i/ && /e/ && /n/ && length($_)<10' /usr/share/dict/words |wc -l	# prints: 18
}
(( 0 )) && {	# bash string operations. 8.  Get the 3rd last string (dots to seperate) from:
	# foo.bar.VALUE.baz.lala 
	# or foor.bar.gigi.VALUE.baz.lala

	# from: Alex S.<[email protected]>
	echo foo.bar.VALUE.baz.lala | awk -F. '{ print $(NF-2); }'

	# from	Stephen Harris <[email protected]>
	# Use IFS to split the string

	a=foo.var.VALUE.baz.lala
	OIFS="$IFS"		# save Internal Field Separator
	IFS="."
	set -- $a		# the positional parms are set to $a
	IFS="$OIFS"		# restore IFS
	SHIFT=$(($# - 3))	# how many positional parms to shift off?
	shift $SHIFT
	echo $1

	# Using string pattern matching

	a=foo.var.VALUE.baz.lala
	front=${a%.*.*.*}	# cut shortest path from end, ie, cut the last three.
	b=${a#$front.}		# cut shortest match from start, leaving the last three.
	b=${b%%.*}		# cut longest match from end, leaving the 3rd from end.
	echo $b

}
(( 0 )) && {	# bash string operations. 7.  take a string and make it an array.

	message='Test Message'
	last=$(expr ${#message} - 1)

	declare -a msg			# array msg will hold individual characters from $message
	for n in $(seq 0 $last)
	do
		msg[$n]="${message:$n:1}"
		echo -e "\t$n: \t${msg[$n]}"
	done
}
(( 0 )) && {	# bash string operations. 6.  Single and Global replacement.

	a='"this got quotation"'
	# echo ${a//\"/}		# global replacement of 
	#prints: this got quotation

	B="Four\nscore\nand\nseven\nyears\nago"
	echo $B
	echo "${B//\\n/ }"
	# prints: Four score and seven years ago
}
(( 0 )) && {	# bash string operations. 5.

	# If $foo exists and is not null, return $foo, else return bar.
	# export foo="" 
	# echo ${foo:-bar} one		# prints: bar one
	# echo $foo			# prints nothing

	# If $foo exists and is not null, return $foo, else set $foo to bar and return bar.
	# export foo=""
	# echo ${foo:=bar} one		# prints: bar one
	# echo $foo one			# prints: bar one

	# If $foo exists and is not null, return bar, else return a null.
	# export foo="this is a test"
	# echo ${foo:+bar}		# prints: bar

	# If $foo exists and isn't null, return its value. 
	# If it doesn't exist or is null, print the error message. 
	export foo=""
	echo ${foo:?"this is an error message"}
}
(( 0 )) && {	# bash string operations. 4.  sub-string operator

	a="abcdef"

	b=${a:0:1}; echo $b	# prints a
	c=${a:0:2}; echo $c	# prints ab
	d=${a:2:2}; echo $d	# prints cd
	e=${a:4};   echo $e	# prints ef
}
(( 0 )) && {	# bash string operations. 3. sub-string operation.  start at specified position.

	devArray=(/dev/hda7 /dev/hda10 /dev/hda11 /dev/hda13)
	mapArray=(${devArray[0]:5} ${devArray[1]:5} ${devArray[2]:5} ${devArray[3]:5})
	# eg: mapArray=(hda7 hda10 hda11 hda13)  ## ":5" means start at position 5, zero based.
	mntArray=(/tmp /mnt/bergen /mnt/trondheim /mnt/oslo)

	for (( i=0 ; i < ${#devArray[@]} ; ++i ))
	do
		echo
		dev=${devArray[$i]} ; echo "  dev: $dev"
		map=${mapArray[$i]} ; echo "  map: $map"
		mnt=${mntArray[$i]} ; echo "  mnt: $mnt"
	done
}
(( 0 )) && {	# bash string operations. 2. "String operations using \"expr \$string : \" construct"

	a=1234zipper5FLIPPER43231

	echo -e "\tString being operated on: \"`expr "$a" : '\(.*\)'`\"."	# note escaped parens.
	echo -e "\tLength: `expr "$a" : '.*'`."					# Length of string
	echo -e "\tNumber of digits at the beginning: `expr "$a" : '[0-9]*'`."

	echo -e "\tDigits at the beginning: `expr "$a" : '\([0-9]*\)'`."
	echo -e "\tFIRST 7 chars: `expr "$a" : '\(.......\)'`."			# parens
	echo -e "\tLAST 7 chars: `expr "$a" : '.*\(.......\)'`."		# note .* before parens.
}
(( 0 )) && {	# bash string operations. 1.

	a=1234zipper43231
	echo -e "\tThe string being operated on is \"$a\"."
	echo -e "\tLength of \"$a\" is $(expr length $a)."
	echo -e "\tNumerical position of first \"2\" in \"$a\" is \"$(expr index $a 23)\"."
	echo -e "\tSubstring of \"$a\", starting at position 2, and 6 chars long is \"$(expr substr $a 2 6)\"."

	#  The default behavior of the 'match' operations is to
	#+ search for the specified match at the ***beginning*** of the string.
	#
	#        uses Regular Expressions
	b=`expr match "$a" '[0-9]*'`		# Numerical count.
	echo -e "\tNumber of digits at the beginning of \"$a\" is $b."

	b=`expr "$a" : '[0-9]*'`		# exact equivalent above
	echo -e "\tNumber of digits at the beginning of \"$a\" is $b."

	b=`expr match "$a" '\([0-9]*\)'`	# escaped parentheses trigger substring match
	echo -e "\tThe digits at the beginning of \"$a\" are \"$b\"."

	b=`expr $a : '\([0-9]*\)'`		# exact equivalent above
	echo -e "\tThe digits at the beginning of \"$a\" are \"$b\"."
}
(( 0 )) && {	# bash string operations. 0.
	# Thanks to Pat Eyler at http://www.linuxjournal.com/article/8919

	export $foo="this is a test"

	# del shortest match from left
	echo ${foo#t*is}		# prints: is a test

	# del longest match from left
	echo ${foo##t*is}		# prints: a test

	# del shortest match from right
	echo ${foo%t*st}		# prints: this is a

	# del longest match from right
	echo ${foo%%t*st}		# prints nothing

	# A convenient mnemonic: 
	# The # key is on the left side of the $ key and operates from the left. 
	# The % key is on the right of the $ key and operates from the right.
}
(( 0 )) && {	# more string operations.
	# Thanks: http://linuxgazette.net/114/okopnik.html

	var="amanuensis"		# Let's pick a nice, longish word to play with.

	echo ${#var}			# ${#var}	- return length.  prints "10"
	echo ${var#*n}			# ${var#word}	- cut shortest match from start.	prints "uensis"
	echo ${var##*n}			# ${var##word}	- cut longest match from start.		prints "sis"
	echo ${var%n*}			# ${var%word}	- cut shortest match from end.		prints "amanue"
	echo ${var%%n*}			# ${var%%word}	- cut longest match from end.		prints "ama"
	echo ${var:7}			# ${var:offset}	- return string starting at 'offset'.	prints "sis"
	echo ${var:1:3}			# ${var:offset:l} - return l chars starting at 'offset'.   prints "man"

	echo ${var/amanuen/paralip}	# ${var/pattern/string}		- replace single match.	prints "paralipsis"
	echo ${var//a/A}		# ${var//pattern/string}	- replace all matches.	prints "AmAnuensis"

	experiment=supercallifragilisticexpialadocious

	echo ${experiment%l*}		# prints "supercallifragilisticexpia"
	echo ${experiment%%l*}		# prints "superca"
	echo ${experiment#*l}		# prints "lifragilisticexpialadocious"
	echo ${experiment##*l}		# prints "adocious"

}
(( 0 )) && {	# Using \b (backspace) for fun and profit.

	echo -en "\tHave a very nice day, Sir."
	sleep 2
	echo -e "\b\b\b\bButtBreath."
}
(( 0 )) && {	# for z22, convert a .jpg file to a .jpg.pdb file
	# thanks: http://www.thehaus.net/index.php?ent=4938	for par usage
	# thanks: http://www.djw.org/product/palm/par/		for par program

	# source: LOGOS2.jpg	destination: LOGOS2.jpg.pdb
	# par c -a "stream" LOGOS2.jpg.pdb LOGOS2.jpg Foto Foto LOGOS2.jpg

	cd /home/ja/public/in_work/pda_images
	from=tom_160.jpg
	to=$from.pdb
	/data/downloads/z22/par/prc/par c -a "stream" test_160.jpg.pdb tom_160.jpg Foto Foto tom_160.jpg

	# The above will create a file test_160.jpg.pdb that I am unable 
	# to install into my z22 with pilot-xfer or pilot-foto.
}
(( 0 )) && {	# pass an array to a function and return an array from the function.

	Pass_Array ()
	{
		local my_local_array
		my_local_array=( $(echo "$1") )		# assign argument to local array variable

		# do something to array.

		echo "${my_local_array[@]}"
	}

	original=( element1 element2 element3 element4 element5 )
	echo -e "\tOriginal: ${original[@]}"		# space-separated list of elements.

	argument=$( echo ${original[@]} )		# Pack a var with a space-separated list of elements
	echo -e "\tArgument: $argument"

	echo -e "\tEchoed  : $(Pass_Array "$argument")" # echo what the function returns.

	returned=( $(Pass_Array "$argument") )		# Assign output of function to array variable.
	echo -e "\tReturned: ${returned[@]}"

	exit 0
}
(( 0 )) && {	# Array basics.

	array=(one two three four [5]=five)

	echo "Array size: ${#array[*]}"

	echo "Array items:"
	for item in ${array[*]}; do printf "   %s\n" $item; done

	echo "Array indexes:"
	for index in ${!array[*]}; do printf "   %d\n" $index; done

	echo "Array items and indexes:"
	for index in ${!array[*]}; do printf "%4d: %s\n" $index ${array[$index]}; done
}
(( 0 )) && {	# sort an array.  send each element of array to a file; sort the file; build new array.

	array1=(a x t g u o p w d f z l)
	echo "Array 1: ${array1[@]}"
	declare -a array2

	touch tmp
	for i in ${array1[@]}; 
	do
		echo $i >> tmp
	done
	sort tmp -o tmp

	while read line; 
	do
		array2=(${array2[@]} $line)
	done < tmp
	rm tmp

	echo "Array 2: ${array2[@]}"
}
(( 0 )) && {	# play with arrays

	declare -a some						# declare array some
	some[0]=zero						# add element to array
	some[1]=one						# ditto
	some[2]="one two"
	some[3]="a b c"

	# echo ${#some[*]}					# prints: 4
	# echo ${some[*]}					# prints: zero one one two a b c
	# for e in "${some[*]}" ; do echo "$e"; done		# prints: zero one one two a b c
	# for e in  ${some[*]}  ; do echo  $e; done		# prints: 7 rows.  burp!
	# for e in  ${some[@]}  ; do echo  $e; done		# prints: 7 rows.  burp!
	echo -e "\n\t===== Just a simple echo"
	for e in   "${some[@]}" ; do echo "$e"; done		# prints: 4 rows.  Yeah!

	### Conclusion, use "${some[@]}"

	some[4]=one						# add redundant element to array
	some[${#some[*]}]=zero					# ditto
	some[${#some[*]}]="a b c"				# ditto

	echo -e "\n\t===== Just a simple echo"
	for e in   "${some[@]}" ; do echo "$e"; done		# prints: 7 rows.

	echo -e "\n\t===== And a sort unique"
	for e in   "${some[@]}" ; do echo "$e"; done |sort -u	# prints: 4 rows.
}
(( 0 )) && {	# using [*] and [@] with/without quotes

	array=("first item" "second item" "third" "item")	# 4 items in array.

	echo "Number of items in original array: ${#array[*]}"	# produces 4 items.  USE This form.
	for ix in ${!array[*]}; do printf "   %s\n" "${array[$ix]}"; done
	echo

	arr=(${array[*]})
	echo "After unquoted expansion: ${#arr[*]}"		# produces 6 items.
	for ix in ${!arr[*]}; do printf "   %s\n" "${arr[$ix]}"; done
	echo

	arr=("${array[*]}")
	echo "After * quoted expansion: ${#arr[*]}"		# produces 1 item.
	for ix in ${!arr[*]}; do printf "   %s\n" "${arr[$ix]}"; done
	echo

	arr=("${array[@]}")
	echo "After @ quoted expansion: ${#arr[*]}"		# procudes 4 items.  OR use this form.
	for ix in ${!arr[*]}; do printf "   %s\n" "${arr[$ix]}"; done
}
(( 0 )) && {	# Read a file, one record per line, 4 fields per record.
	# NB: structured data file, no tabs, just spaces and newlines.
	# Thanks: http://linuxgazette.net/114/okopnik.html

	fn=/home/ja/temp/temp_fn_$$
		#23456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789
	cat <<-_BOINK_ > $fn
		Jim & Fanny Friends     Business   101101 Digital Dr. LA CA        [email protected]
		Fred & Wilma Rocks      friends    12 Cave St. Granite, CT         [email protected]
		Joe 'Da Fingers' Lucci  Business   45 Caliber Av. B-klyn NY        [email protected]
		Yoda Leahy-Hu           Friend     1 Peak Fribourg Switz           [email protected]
		Cyndi, Wendi, & Myndi   Friends    5-X Rated St. Holiday FL        [email protected]
	_BOINK_

	declare -a name category address email		# explicitly declare these variables as arrays.

	OLD=$IFS					# save intra field seperator
	IFS='
	'

	for line in $(cat $fn)
	do
		((x++))							# Inc line counter

		name[$x]="${line:0:24}"					# load the 'name' variable
		name[$x]="$(echo ${name[$x]} |sed -e 's/ *$//')"	# remove trailing spaces

		category[$x]="${line:24:11}"
		category[$x]="$(echo ${category[$x]} |sed -e 's/ *$//')"

		address[$x]="${line:35:32}"
		address[$x]="$(echo ${address[$x]} |sed -e 's/ *$//')"

		email[$x]="${line:67:20}"
		email[$x]="$(echo ${email[$x]} |sed -e 's/ *$//')"

		# printf "\t%-24s %-11s %-32s %-20s \n" ${name[$x]} ${category[$x]} ${address[$x]} ${email[$x]}
	done

	IFS=$OLD					# restore $IFS

	echo -e "\n\tLook for records with category = friends \n"
	for y in $(seq $x)
	do
		if [ -z "${category[$y]##[Ff]riend*}" ]
		then
			printf "\t%-24s %-11s %-32s %-20s \n" "${name[$y]}" \
				"${category[$y]}" "${address[$y]}" "${email[$y]}"
		fi
	done
}
(( 0 )) && {	# Where did this come from ????

	echo Where did this come from?

	# Never write it in 'C' if you can do it in 'awk';
	# Never do it in 'awk' if 'sed' can handle it;
	# Never use 'sed' when 'tr' can do the job;
	# Never invoke 'tr' when 'cat' is sufficient;
	# Avoid using 'cat' whenever possible.
	# -- Taylor's Laws of Programming
}
(( 0 )) && {	# make tempfile within temp dir

	TDIR=$(mktemp -d ~ja/temp/tempdir.XXXXXXXXXX)	|| exit 1
	TFILE=$(mktemp $TDIR/tempfile.XXXXXXXXXX)	|| exit 1
	echo -e "\tTDIR: $TDIR \t TFILE: $TFILE "
}
(( 0 )) && {	# With FireFox, print to a file, eg hayward_viper.ps, then convert to pdf.

	ps2pdf hayward_viper.ps hayward_viper.pdf
}
(( 0 )) && {	# Which pdf utilities might be useful

	ls /usr/bin/*pdf* |while read F; 
	do 
		P=$(rpm -qf $F); 
		printf "  %30s : %s \n"  "$P" "$F"; 
	done \
		|egrep -v 'docbook|ghost|tetex|xmltex|texinfo|foo|jade' \
		|sort >> ~ja/temp/pdf_options

	# prints:
	#	Package				Utility			Purpose
	#--------------------------------   ---------------------        -------------------
	#         kdegraphics-3.5.9-1.fc7 : /usr/bin/kpdf		# reader
	#             libtiff-3.8.2-8.fc7 : /usr/bin/tiff2pdf 		# tiff to pdf
	#             pdfedit-0.3.2-2.fc7 : /usr/bin/pdfedit		# editor, immature
	#                pdftk-1.41-5.fc7 : /usr/bin/pdftk		# EOL due to license problems
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdffonts		# font analyzer
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdfimages		# extract images
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdfinfo		# pdf info
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdftohtml		# 
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdftoppm		# 
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdftops		# 
	#       poppler-utils-0.5.4-8.fc7 : /usr/bin/pdftotext		# 
	#                 xpdf-3.02-4.fc7 : /usr/bin/xpdf		# reader
}
(( 0 )) && {	# extract images and text from a pdf document

	/usr/local/bin/pdfimages -f 40 -l 43 -j dpf_file_name image_prefix
	/usr/local/bin/pdftotext -f 40 -l 43 dpf_file_name text_filename
}
(( 0 )) && {	# Using poppler-tools and psutils, extract a range of pages from a PDF.
	# For example, extract pages 11–14 of the PDF file afile.pdf

	pdftops afile.pdf - | psselect -p11-14 | ps2pdf - file-p11-14.pdf
}
(( 0 )) && {	# use xmlwf to check if an xml document is well formed

	# the first, third, and fourth files are well formed.  
	# the second (test_wf.xml) is not.  An early start tag was changed.
	# it issues a result like:
	#	Result for file .../test_wf.xml: .../test_wf.xml:24:2: mismatched tag
	# which identifies what should be the closing tag as a mismatch.

	for f in						\
		/home/ja/public/linux/database/dbd4/books.xml	\
		/home/ja/public/linux/database/dbd4/test_wf.xml	\
		/home/ja/public/kin/a/bloglines_export.xml	\
		/home/ja/.gaim/prefs.xml
	do
		# If normal file, check WF-ness.  Result => not WF, so print result.  No result => WF.
		res='' && [ -f $f ] && res=$( /usr/bin/xmlwf $f ) && [ ${#res} -gt 0 ] && echo -e "\tResult: $res"

	done

	# see also: ~ja/bin/well_formed_check.sh
	# which could be used in a "find" command, ie:
	# find . -iname '*.xml' -type f -execdir ~/bin/well_formed_check.sh {} \;

}
(( 0 )) && {	# make sure html file permissions are 644 for web page dirs.

	for fn in fun hardware in_work kin linux nontech web
	do
		find ~/public/$fn -iname '*.html' -type f -execdir chmod 644 {} \;

		if [  $(find ~/public/$fn -iname '*.html' -type f -execdir ls -dl {} \;  |grep -v '\-rw\-r\-\-r\-\-' |wc -l) -gt 0 ]
		then
			find ~/public/$fn -iname '*.html' -type f -execdir ls -dl {} \;  |grep -v '\-rw\-r\-\-r\-\-' |less
		fi
	done
}
(( 0 )) && {	# make sure dir permissions are 755 for web page dirs.

	for dir in fun hardware in_work kin linux nontech web
	do
		find ~/public/$dir  -type d -execdir chmod 755 {} \;

		if [  $(find ~/public/$dir -type d -execdir ls -dl {} \; |grep -v 'drwxr-xr-x' |wc -l) -gt 0 ]
		then
			find ~/public/$dir -type d -execdir ls -dl {} \; |grep -v 'drwxr-xr-x' |less
		fi
	done
}
(( 0 )) && {	# given IP address, find MAC address.  on same lan

	ip=192.168.0.12

	ping -c 1 $ip >/dev/null	# tiny pings quiettoo.  count (c) of 1.
	/sbin/arp -a $ip		# retrieve from arp cache

}
(( 0 )) && {	# switch stderr and stdout.  test stderr for condition and then act.
	# thanks to "Linux Server Hacks" by Rob Flickenger.

	[ ! $(whoami) = 'root' ]  &&  echo "Must be root to execute."  &&  exit

	if [ $(crontab -u elh -l 3>&2 2>&1 1>&3 |grep "no crontab" |wc -l) -eq 1 ]; then echo Gotcha; fi

}
(( 0 )) && {	# Find the largest 20 files.  Thanks: "Rick Moen" <[email protected]>

	### find options:
	#
	# -xdev and -mount:	Don't descend dirs on other filesystems.
	#
	# -print0:		Print full fn, followed by null char.
	#			Then use `-0' or `--null' option to GNU xargs, GNU tar, GNU cpio, or perl.
	### xargs options:
	#
	# --null or -0:		Terminate filenames with null char (not whitespace).
	#			Quotes and backslash are not special  (every char is taken literally).
	#			Useful when args might contain white space, quote marks, or backslashes.
	#			GNU find -print0 option produces input suitable for this mode.
	#
	# -r:			If the standard input does not contain any nonblanks, 
	#			do not run the command.
	#			Normally, the command is run once even if there is no input.
	echo
	echo "The 20 largest files in or under `pwd`:"
	find . -xdev -type f -print0 | xargs -r0 ls -l | sort -rn +4 | head -n 20		# nice and fast
}
(( 0 )) && {	# see if a user has a password

	# /etc/shadow has encrypted 34-character user password in the second position
	# Or, the second position may contain "x", "*", "!!" or null
	# So, if the lenght of the character string is greater than 2, the user has an encrypted password

	fn=/etc/shadow

	for u in ja elh guest
	do
		pw=$(cat $fn |grep ^$u: |cut -d ':' -f 2)
		# len=${#pw}
		# echo -e "\tLenght of password for user $u: \t$len"
		# [ $len -gt 2 ]  &&  echo -e "\tUser $u has a password."
		[ ${#pw} -gt 2 ]  &&  echo -e "\tUser $u has a password."
	done
}
(( 0 )) && {	# several commands might work.  find one that is installed

	# from the bash manual: "type [-aftpP] name [name ...]", 
	# With no options, indicate how each name would be interpreted if used as a command name.
	# If the -t option is used, type prints a string  which  is  one  of alias, keyword, function, builtin, or 
	# file if  name  is  an  alias,  shell  reserved  word,  function, builtin,  or disk file, respectively.
	# type returns true  if any of the arguments are found, false if none are found.

	if type w3m >/dev/null 2>&1;	then echo -e "\tWe have w3m"  
	elif type lynx >/dev/null 2>&1;	then echo -e "\tWe have lynx"  
	else				echo -e "\t$0: can't find w3m or lynx"; exit 1
	fi
}
(( 0 )) && {	# Deal with special characters that may come via .doc -> OOo -> plain text
	# Replace with entities: rsquo, lsquo, rdquo, ldquo, apos, hellip, ndash, mdash
	# ToDo
	#	- lsquo
	#	- apos		needed?

	ttt="/home/ja/temp/ttt.temp"
	echo

	# for fn in ~/public/kin/gg/test/{01,28}*
	for fn in $(ls ~/public/kin/gg/test/* |grep -v '.txt')
	do
		echo $fn
		cat $fn |sed	-e 's/…/\&hellip\;/'	\
				-e 's/\’/\&rsquo\;/'	\
				-e 's/\©/\&copy\;/'	\
				-e 's/\–/\&ndash\;/g'	\
				-e 's/\—/\&mdash\;/'	\
				-e 's/\“/\&ldquo\;/g'	\
				-e 's/\”/\&rdquo\;/g'	\
				> $ttt

		[ -f $fn ] && [ -f $ttt ] && rm $fn && mv $ttt $fn
	done
}
(( 0 )) && {	# using getopts

	[ $# -eq 0 ]  &&  echo "Error msg"  &&  exit 65

	while getopts ":mnopq:rs" Option
	do
		case $Option in
			m     ) echo -e "\tScenario #1: option -m-  [OPTIND=${OPTIND}]";;
			n | o ) echo -e "\tScenario #2: option -$Option-  [OPTIND=${OPTIND}]";;
			p     ) echo -e "\tScenario #3: option -p-  [OPTIND=${OPTIND}]";;
			q     ) echo -e "\tScenario #4: option -q-  with argument \"$OPTARG\"  [OPTIND=${OPTIND}]";;
			r | s ) echo -e "\tScenario #5: option -$Option-";;
			*     ) echo -e "\tUnimplemented option chosen.";;   # DEFAULT
		esac
	done
	shift $(($OPTIND - 1))		# just the args remain in $*

	# [ja@pacific ~]$ ~/bin/code_bash.sh -mnopqboink -rs
	#	Scenario #1: option -m-  [OPTIND=1]
	#	Scenario #2: option -n-  [OPTIND=1]
	#	Scenario #2: option -o-  [OPTIND=1]
	#	Scenario #3: option -p-  [OPTIND=1]
	#	Scenario #4: option -q-  with argument "boink"  [OPTIND=2]
	#	Scenario #5: option -r-
	#	Scenario #5: option -s-
}
(( 0 )) && {	# have several levels of verbosity

	vlevel=0
	while getopts "v" flag; do
	    case $flag in
		v)	vlevel=$((vlevel +1))	;;
		*)	echo -e "\tKindly specify -v or -vv ... or nothing"; exit 1 ;;
	    esac
	done
	echo -e "\tVlevel: $vlevel"
}
(( 0 )) && {	# manipulate options and arguments.  call as: $0 -a aaa -b bbbb -c option_one *.jpg

	echo -e "\t parms: $*"	# prints: -a aaa -b bbbb -c option_one and expanded *.jpg files.

	while getopts "a:b:c" flag; do
	    case $flag in
		a)	my_a="$OPTARG"	;;
		b)	my_b="$OPTARG"	;;
		c)	my_c="true"	;;
		\?)	echo "usage: $0 -a aaa -b bbb -c argument_1 arg_2 ..."; exit 1 ;;
	    esac
	done

	echo -e "\t options: a: $my_a, b: $my_b, c: $my_c"	# as expected.
	echo -e "\t m: ${OPTIND}, n: ${!OPTIND}"		# m: 6, n: option_one, 
	first_arg=${!OPTIND};				# ${!xxxx} is an "indirect reference", ie, value of $6.
	echo -e "\t first arg: $first_arg"		# first arg: option_one
	shift $OPTIND					# shift off first 6 parms.
	echo -e "\t parms: $*"				# parms: just the expanded .jpg files.
}
(( 0 )) && {	# SELinux utilities for mode of operation.  # 1=enforceing, 0=permissive

	echo $(/usr/sbin/getenforce)			# prints: Enforcing

	if [ /usr/sbin/selinuxenabled ]			# prints enabled
	then echo enabled
	else echo disabled
	fi

	/usr/sbin/setenforce 0
	echo $(/usr/sbin/getenforce)			# prints: Permissive

	if [ /usr/sbin/selinuxenabled ]			# prints enabled
	then echo enabled
	else echo disabled
	fi

	/usr/sbin/setenforce 1
	echo $(/usr/sbin/getenforce)			# prints: Enforcing

	if [ /usr/sbin/selinuxenabled ]			# prints enabled
	then echo enabled
	else echo disabled
	fi

}
(( 0 )) && {	# determine "device" in prep for cdrecord

	address=$(/usr/bin/cdrecord -scanbus |grep Removable |awk '{print $1}';) 1>/dev/null 2>/dev/null
	hn=$(/bin/hostname -s)

	case $hn in
		pacific)	d=burp		;;
		quietone)	d=$address	;;
		quiettoo)	d="ATAPI:$hn"	;;
		*)		d=double_burp	;;
	esac
	echo -e "\t Hostname: $hn \t device: $d "
}
(( 0 )) && {	# Spelling

	echo -e "\nTest 1.  correct spelling => heading only"
	echo compatible|aspell -a 

	echo -e "\nTest 2.  incorrect spelling => heading and some options"
	echo compatable|aspell -a

	echo -e "\nTest 3.  Spell check a file.  prints mis-spelled words."
	fn=/home/ja/temp_fn_$$
	cat <<-_BOINK_ > $fn
		Now is the time for all good men ansd women
		to come to the aid of their country.

		Four score and seven years ago, out for-fathers brought forth in this continant,
		a new nation, concieved in liberaty and dedicated to the proposition that all 
		men are created equal.
	_BOINK_
	spell $fn
	rm $fn

	echo -e "\nTest 4.  Look in dict for words matching _active_."
	look active			# prints active and actively

	echo -e "\nTest 5.  Look in dict for words matching _inkorrectrly_."
	look inkorrectrly		# no output

	echo -e "\nTest 6.  Look in dict for words matching _percei_."
	look percei			# prints 8 matching words
}
(( 0 )) && {	# process chunks of data from some program.  (Thanks to Jerry Peek, Linux Mag., Oct 2004)

	fn=/etc/httpd/conf/httpd.conf

	cat $fn |
	while :
	do
		chunk=$(dd count=1 bs=1024 2>/dev/null)
		# test -z "$chunk" && break
		[ -z "$chunk" ]  &&  break
		echo -n "."			# do processing here for each chunk
						# in this case, prints 35 dots.
	done
}
(( 0 )) && {	# less options

	# Created by Ben Okopnik on Sun Jun 13 11:03:00 EDT 2004

	p="Press 'q' to quit"
	q="'direct rendering' should be marked 'Yes'\. $p"
	r="Press 'n' to see the next warning or error"

	LIBGL_DEBUG=verbose glxinfo 2>&1 |less -P"$q"
	dmesg |egrep -i 'agp|drm' |less -P"$p"
	less  -P "$r"  -p "\(WW|EE\)" /var/log/XFree86.0.log
}
(( 0 )) && {	# parse logfile

	logfile='/var/log/httpd/error_log.2'
	(
		echo "Here is a report of the top 20 'missing' files in $logfile"
		echo
		for x in `grep "File does not exist:" $logfile |awk '{print $13}' |sort |uniq`; 
		do 
			grep $x $logfile | wc -l | tr -d '\n'
			echo " : $x"
		done | sort +2 -rn | head -n 20

	) | mail -s "Missing File Report" ja@quiettoo
}
(( 0 )) && {	# send mail from within bash	( <<- means remove leading tab characters. )
	mail -s 'a subject line' ja@localhost	> /dev/null 2> /dev/null <<- "ENDMAIL"
		This is line 1 of the body of the email message.
		This is line 2 of the body of the email message.
		This is line 3 of the body of the email message.
		This is line 4 of the body of the email message.
		This is line 5 of the body of the email message.
		This is line 6 of the body of the email message.
		This is line 7 of the body of the email message.
		This is line 8 of the body of the email message.
		This is line 9 of the body of the email message.
	ENDMAIL
}
(( 0 )) && {	# Get files/documents using curl	(thanks to Linux Journal)
	#
	# from article.  -s=silent -i=include_http_header  -H=Header

	curl -s -i -H "Referer: http://www.livejournalx.com" 'http://www.notbig.org/fam/jim_tn.jpg' | head -n 1
	# curl -s -i -H "Referer: http://www.livejournal.com"  'http://www.notbig.org/fam/jim_tn.jpg' | head -n 1
	# curl -s -i                                           'http://www.notbig.org/fam/jim_tn.jpg' | head -n 1
	# results: HTTP/1.1 200 OK

	# -v=verbose, use own jpg.
	# curl -v -i 'http://www.notbig.org/fam/jim_tn.jpg' | head		# results: 25 lines of header stuff.
	# curl -i    'http://www.notbig.org/fam/jim_tn.jpg' | head -n 1		# results: download stats

	# curl -s -i 'http://www.notbig.org/fam/lists.php' | head -n 1		# results: HTTP/1.1 200 OK
	# curl -s -i 'http://www.notbig.org/fam/lists.php' > curl_output	# headers, blank line, file contents

	# -I=head only
	# curl -I -s -i 'http://www.notbig.org/fam/lists.html' > curl_output	# results: nothing
	# curl -I -i 'http://www.notbig.org/fam/lists.html' > curl_output	# results: stats
}
(( 0 )) && {	# check /var/run for files named *.pid
	# do a "kill -0 PID" and check return code to see if process is processing signals.
	# OR, just parse ps output.

	for F in /var/run/atd.pid
	do
		PID=$(cat $F |head -n 1)
		kill -0 $PID
		errmsg=$?
		printf "  Process: %-25s \tPID: %-8s \tErrorMsg: %s \n" "$F" "$PID" "$errmsg"
	done
}
(( 0 )) && {	# This script traps CTRL-C (SIGINT) and CTRL-Z (SIGTERM)
	# 
	# when run in the foreground:
	#	CTRL-C (interrupt) will result in a message,
	#	CTRL-Z (suspend) will stop the script and put it in the bg
	#	use fg to get it in the fg
	#	use 'kill -KILL %2' to really kill it (after a suitable delay).
	#
	# when run in bg, the script will NOT respond to either signal

	trap "echo 'You hit control-C!'"		INT	# ctrl c
	trap "echo 'You tried to terminate me!'"	TERM	# ctrl z
	trap 'echo "exiting script"'			EXIT	# finish normally, or by an explicit 'exit', or by getting a 'INT' or 'TERM' signal

	while true; do
		echo -n "sleeping, "
		sleep 4
	done
}
(( 0 )) && {	# "kill" info

	echo
	# [ja@hudson ~]$ kill -l
	#  1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL
	#  5) SIGTRAP      6) SIGABRT      7) SIGBUS       8) SIGFPE
	#  9) SIGKILL     10) SIGUSR1     11) SIGSEGV     12) SIGUSR2
	# 13) SIGPIPE     14) SIGALRM     15) SIGTERM     16) SIGSTKFLT
	# 17) SIGCHLD     18) SIGCONT     19) SIGSTOP     20) SIGTSTP
	# 21) SIGTTIN     22) SIGTTOU     23) SIGURG      24) SIGXCPU
	# 25) SIGXFSZ     26) SIGVTALRM   27) SIGPROF     28) SIGWINCH
	# 29) SIGIO       30) SIGPWR      31) SIGSYS      34) SIGRTMIN
	# 35) SIGRTMIN+1  36) SIGRTMIN+2  37) SIGRTMIN+3  38) SIGRTMIN+4
	# 39) SIGRTMIN+5  40) SIGRTMIN+6  41) SIGRTMIN+7  42) SIGRTMIN+8
	# 43) SIGRTMIN+9  44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12
	# 47) SIGRTMIN+13 48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14
	# 51) SIGRTMAX-13 52) SIGRTMAX-12 53) SIGRTMAX-11 54) SIGRTMAX-10
	# 55) SIGRTMAX-9  56) SIGRTMAX-8  57) SIGRTMAX-7  58) SIGRTMAX-6
	# 59) SIGRTMAX-5  60) SIGRTMAX-4  61) SIGRTMAX-3  62) SIGRTMAX-2
	# 63) SIGRTMAX-1  64) SIGRTMAX

	# See /usr/include/asm/signal.h on Fedora8 for name and number.

	# From: "Filipe Brandenburger" <[email protected]>
	# > aux' and issue the command 'kill -9 pidofprocess'. If you know the
	# > name of the process you may use 'killall -9 processname'.
	# ...
	# Why the hell -9?
	# TERM is -15 and HUP is -1 (but I would stick to the names).
	# Using -9 is almost always the wrong answer. It's a last resort when everything else failed, 
	# and it should be reserved for such.  One should never use this command on a day-to-day basis, 
	# much less teach it or suggest it in a mailing list like this one.

	# From Randal L. Schwartz
	# No no no.  Don't use kill -9 (SIGKILL).
	# It doesn't give the process a chance to cleanly:
	# 1) shut down socket connections
	# 2) clean up temp files
	# 3) inform its children that it is going away
	# 4) reset its terminal characteristics
	# and so on and so on and so on.
	# Generally, send 15 (SIGTERM), wait 1-2 sec, then send 2 (SIGINT), and if that doesn't work, send 1 (SIGHUP).  
	# If that doesn't, REMOVE THE BINARY because the program is badly behaved!

	# So: "kill -15 pids", wait, "kill -2 pids", "kill -1 pids"
}
(( 0 )) && {	# More "kill" info

	echo
	# From "info kill":
	#
	# The following signal names and numbers are supported on all POSIX compliant systems:
	#
	# `HUP'		1.  Hangup.
	# `INT'		2.  Terminal interrupt.
	# `QUIT'	3.  Terminal quit.
	# `ABRT'	6.  Process abort.
	# `KILL'	9.  Kill (cannot be caught or ignored).
	# `ALRM'	14.  Alarm Clock.
	# `TERM'	15.  Termination.
	#
	# Other supported signal names have system-dependent corresponding numbers.  
	# All systems conforming to POSIX 1003.1-2001 also support the following signals:
	#
	# `BUS'		Access to an undefined portion of a memory object.
	# `CHLD'	Child process terminated, stopped, or continued.
	# `CONT'	Continue executing, if stopped.
	# `FPE'		Erroneous arithmetic operation.
	# `ILL'		Illegal Instruction.
	# `PIPE'	Write on a pipe with no one to read it.
	# `SEGV'	Invalid memory reference.
	# `STOP'	Stop executing (cannot be caught or ignored).
	# `TSTP'	Terminal stop.
	# `TTIN'	Background process attempting read.
	# `TTOU'	Background process attempting write.
	# `URG'		High bandwidth data is available at a socket.
	# `USR1'	User-defined signal 1.
	# `USR2'	User-defined signal 2.
	#
	# ... and so on.
}
(( 0 )) && {	# Weak example.  Send cli text to an email account.  Prevent an INT or TERM from 
	# leaving a mess.
	#
	# if this script is interrupted by a signal, then 'rm $msgfile' may not get run
	# so, trap signals and run function cleanup
	#
	
	function cleanup {
	    if [ -e $msgfile ]; then mv $msgfile dead.letter; fi
	    exit
	}

	trap cleanup INT TERM

	msgfile=/home/ja/temp/msg_temp_$$		# $$=pid
	cat > $msgfile					# cli text to $msgfile
	# send $msgfile to an email address...
	rm $msgfile
}
(( 0 )) && {	# Issue a message on termination.
	#
	:
	trap 'echo Thank you for playing' EXIT

	magicnum=$(($RANDOM%10+1))			# ???
	echo 'Guess a number between 1 and 10:'

	while echo -n 'Guess: ' >&2 ; read guess;
	do
		sleep 1
		if [ "$guess" = $magicnum ]; then
			echo 'Right!'
			exit
		fi
		echo 'Wrong!'
	done
}
(( 0 )) && {	# review files from remote hosts

	# NB: ssh keys pairs must be setup prior.  Eg, on fundy:
	cd ~ja/.ssh
	scp ./id_dsa.pub baffin:.ssh/authorized_keys2

	# copy remote file to local.
	scp ja@baffin:/etc/yum/yum-updatesd.conf ~ja/temp/baffin_yum-updatesd.conf

	echo
}
(( 0 )) && {	# Push a file to several remote servers.
	# This would be more useful w/o a password prompt.
	# Could be put in .bashrc

	work_server[0]="quietone"
	work_server[1]="quiettoo"
	work_server[2]="pacific"

	function servers()
	{
		for host in "${work_server[@]}"
		do
			scp $1 ja@$host:$2
		done
	}
	servers $1 $2
}
(( 0 )) && {	# remote into baffin, run uname -a, send results to local pipeline.

	ssh baffin uname -a |cut -d'#' -f1
}
(( 0 )) && {	# Run an X app on a remote server.  (X11 forwarding)

	# ssh -Y ja@shuttle				# setup forwarding.
	# then run an X app, like gedit

	# ssh -Y ja@shuttle 'gedit'			# do it on 1 line.

	echo "Kindly enter password for ja on shuttle"	# a helpful message.
	ssh -Y ja@shuttle 'gedit'

	# ssh -Y ja@tiny 'nautilus --no-desktop --browser'
	# ssh -Y ja@tiny 'gnome-terminal'
	# ssh -Y ja@tiny 'oocalc'			# spreadsheet on tiny
}
(( 0 )) && {	# Create a key pair

	# Generate a key if necessary:
	mkdir -p ~/.ssh
	chmod 700 ~/.ssh
	cd ~/.ssh
	ssh-keygen -t dsa

	# Or:
	# -N=new_passphrase  -f=filename_of_keyfile.
	ssh-keygen -N '' -f ~/.ssh/id_dsa

	# Copy the public key to the remote host:
	scp -p id_dsa.pub remoteuser@remotehost:

	# Log into the remote host and install the public key:
	ssh -l remoteuser remotehost

	mkdir -p ~/.ssh
	chmod 700 ~/.ssh
	cat id_dsa.pub >> ~/.ssh/authorized_keys	# Appending
	chmod 600 ~/.ssh/authorized_keys
	mv id_dsa.pub ~/.ssh				# Optional
	logout

	# Or:
	#cat ~/.ssh/id_rsa.pub | ssh <REMOTE_SERVER> 'cat - >> ~/.ssh/authorized_keys2'
	# Or:
	#ssh-copy-id <REMOTE_SERVER>
}
(( 0 )) && {	# With SSH you can also automatically login to a remote server, 
	# gzip a series of files or folders, and 
	# transfer the resulting tarball to your local machine, 
	# without creating archives on the remote machine!
	#
	# from: http://www.linux.com/article.pl?sid=06/02/21/2025220

	# Seems best to same login at each host.  else, permissions 
	# can be a problems.  ??

	# ja login to quietone
	from=/tmp/90
	to=/home/ja/temp/test_elh_backup-`date +%Y%m%d`.tar.gz
	ssh ja@quietone "tar czpf - $from" | cat > $to
}
(( 0 )) && {	# capture host loads from "uptime". Save to file. 
	# NB: Better have SSH setup to NOT prompt for password.
	
	getLoad ()
	{
		ssh ja@$1 "export TERM=linux; uptime" |
			sed -e 's/^.*load average://' |
			awk -F',' '{print $1,$2,$3}'
	}

	for HOST in quiettoo quietone
	do
		echo $HOST: $(getLoad $HOST) >> ~ja/public/in_work/uptime_loads/uptime_load_$HOST
	done
}
(( 0 )) && {	# copy a tree on one server to a location on another server.  preserve permissions.
	# p=perserve-permissions
	#
	cd /home/ja/etc

	tar -czf - config/ | ssh pacific "cd /home/ja; mv config config.bak; tar xzpf -"
}
(( 0 )) && {	# Create a ramdisk

	MOUNTPT=/mnt/ramdisk
	SIZE=500				# blocks
	BLOCKSIZE=1024				# 1K block size
	DEVICE=/dev/ramdisk-test		# ramdisk

	[ "$UID" -ne "0" ]  &&  echo -e "\nMust be run by root. \n"  &&  exit 1

	mkdir -p $MOUNTPT

	IF='if=/dev/zero'			# code folding vs dd
	eval "/bin/dd ${IF} of=$DEVICE count=$SIZE bs=$BLOCKSIZE"		# Zero out RAM device.

	mke2fs $DEVICE				# Create an ext2 filesystem on it.
	mount $DEVICE $MOUNTPT			# Mount it.
	chmod 777 $MOUNTPT			# Enables ordinary user to access ramdisk.
						# However, must be root to unmount it.

	echo -e "\n\t\"$MOUNTPT\" now available for use by ordinary users."
}
(( 0 )) && {	# Creating a swapfile.

	FILE=/root/swap
	MINBLOCKS=40

	[ "$UID" -ne "0" ]  &&  echo -e "\nMust be root. \n"  &&  exit 1

	blocks=${1:-$MINBLOCKS}						# Default is 40 blocks.
	[ "$blocks" -lt $MINBLOCKS ]  &&  blocks=$MINBLOCKS		# At least 40 blocks long.


	echo -e "\tCreating swap file of size $blocks blocks (KB)."
	IF='if=/dev/zero'			# code folding vs dd
	eval "dd $IF of=$FILE bs=1024 count=$blocks"			# Zero out file.

	mkswap $FILE $blocks						# Designate it a swap file.
	swapon $FILE							# Activate swap file.

	echo "Swap file created and activated."
	exit 0
}
(( 0 )) && {	# play with od and dd.  (Thanks to Jerry Peek, Linux Mag., Oct 2004)

	echo "Sending 137 bytes of random to a file"
	#dd if=/dev/urandom of=/home/ja/temp/myrand bs=1 count=137

	echo "looking at the file with od"
	od -b /home/ja/temp/myrand
	echo "Note that some of these bytes are legal characters"
}

(( 0 )) && {	# Invoking bc using command substitution in combination with a here document.

	var1=`bc <<- EOF
		18.33 * 19.78
		EOF`
	echo -e "\t$var1 "			# 362.56

	#  $( ... ) notation also works.
	v1=23.53
	v2=17.881
	v3=83.501
	v4=171.63

	var2=$(bc <<- EOF
		scale = 4
		a = ( $v1 + $v2 )
		b = ( $v3 * $v4 )
		a * b + 15.35
		EOF)
	echo -e "\t$var2 "			# 593487.8452

	var3=$(bc -l <<- EOF			# The "-l" option calls the 'bc' math library.
		scale = 9
		s ( 1.7 )			# Returns the sine of 1.7 radians.
		EOF)
	echo -e "\t$var3 "			# .991664810
}
(( 0 )) && {	# Calculate hypotenuse of a right triangle. 2.
	hyp=
	hypotenuse ()
	{
		hyp=$(bc -l <<- EOF
			scale = 9
			sqrt ( $1 * $1 + $2 * $2 )
			EOF)			# But, can't return floating point values from a Bash function.
	}
	hypotenuse 3.68 7.31
	echo -e "\tHypotenuse = $hyp"		# 8.184039344
}
(( 0 )) && {	# Calculate hypotenuse of a right triangle. 1.

	hypot()
	{
		local hypot
		hypot=$(bc -l <<- EOF
			scale = 9
			sqrt ( $1 * $1 + $2 * $2 )
			EOF)
		echo $hypot		
		# echo the result.  acts as "returning" a value.
	}
	echo -e "\tHypot = $(hypot 3.68 7.31)"	# 8.184039344
	echo -e "\tHypot = $(hypot 5 12)"	# 13.000000000
	echo -e "\tHypot = $(hypot 12 12)"	# 16.970562748
}
(( 0 )) && {	# Calculate hypotenuse of a right triangle. 0.

	hypot ()
	{
		echo $(bc -l <<- EOF
			scale = 9
			sqrt ( $1 * $1 + $2 * $2 )
			EOF)
	}
	echo -e "\tHypot = $(hypot 3.68 7.31)"	# 8.184039344
	echo -e "\tHypot = $(hypot 5 12)"	# 13.000000000
	echo -e "\tHypot = $(hypot 12 12)"	# 16.970562748
}
(( 0 )) && {	# bc - An arbitrary precision calculator language

	# length is number of digits.  scale is number of decimal digits.
	# thanks: december 2006 www.linuxjournal.com, Dave Taylor.

	echo "scale=2; 3000 / 3001" |bc		# prints: .99
	echo "scale=6; 3000 / 3001" |bc		# prints: .999666
}
(( 0 )) && {	# Create an image of a data CD using dd, where CD drive is /dev/hdc
	# thanks to www.linux-magazine.com, june 2005 issue.

	dd if=/dev/hdc of=cd.iso
}