rename files to a random filename with 5 digits that contain random numbers and letters

uniqRename.sh

#!/usr/bin/env bash

# IRC Issue from helperW
# Network: freenode
# Channel: #macosx

# I have a directory with  001.png 023.png 003.png ( around 800 files)
# I have to rename them to a random filename with : 5 digits that contain random numbers and letters

# ensure all vars are initialised and exit on error
set -o nounset
set -e

e_header() {
    printf "\n$(tput setaf 7)%s$(tput sgr0)\n" "$@"
}
# debug logging
e_debug() {
    printf "$(tput setaf 2)%s$(tput sgr0)\n" "$@"
}

# Success logging
e_success() {
    printf "$(tput setaf 64)✓ %s$(tput sgr0)\n" "$@"
}

# Error logging
e_error() {
    printf "$(tput setaf 1)x %s$(tput sgr0)\n" "$@"
}

# Warning logging
e_warning() {
    printf "$(tput setaf 136)! %s$(tput sgr0)\n" "$@"
}

# Ask for confirmation before proceeding
seek_confirmation() {
    printf "\n"
    e_warning "$@"
    read -p "Continue? (y/n) " -n 1
    printf "\n"
}

# Test whether the result of an 'ask' is a confirmation
is_confirmed() {
    if [[ "$REPLY" =~ ^[Yy]$ ]]; then
      return 0
    fi
    return 1
}

file_exists() {
    if [ -e "$1" ]; then
      return 0
    fi
    return 1
}

# this is only used to prepare test files
prepSampleFiles(){

	numFiles=100

	# see if first param is really set then check if it is a number
	if [ -n "$1" ]; then
		if ! [[ "$1" =~ ^[0-9]+$ ]] ; then
			e_error "Aborting sample file prep - parameter is not a number"
			exit 33
		else
			numFiles=$1
		fi
	fi

	# check if empty - in sub shell so we don't have to reset the shopts
	files=($(shopt -s nullglob;shopt -s dotglob; echo *))

	if [ ${#files[@]} -gt 0 ]; then 
		seek_confirmation "Directory not empty, do you want to empty the directory?"
		if is_confirmed; then
			$(shopt -s nullglob;shopt -s dotglob;rm *)
		else
			e_error "Aborting sample file prep - directory not empty"
			exit 44
		fi
	fi

	e_debug "Creating $numFiles random sample $ext files"

	START=1
	for i in $(eval echo "{$START..$numFiles}")
	do 
		echo $RANDOM > "$i.$ext"
	done
	# create some dupes
	e_debug "Creating 3 duplicate $ext files"

	if file_exists "1.$ext"; then
		cp 1.png xx1.$ext
		cp 1.png xxx1.$ext
		cp 1.png xxxx1.$ext
	else
		e_warning "Dupe files not created"
	fi

	e_success "prepSampleFiles complete"

	exit 77
}

function usage {

	me=$(basename ${BASH_SOURCE[0]})

	e_header "Usage: $me [-p [NUM]] [-e EXT]"
	echo
	echo "Rename all $ext files in the current directory to have a unique 5 character alphanumeric name"
	echo 'Usually just run with no options'
	echo
	echo 'Options:'
	echo -e '\t-p  - prepare 100 (default) sample files in the current directory'
	echo -e '\t-p NUM - prepare NUM sample files in the current directory'
	echo -e '\t-e EXT - file extension of the files to be renamed'

	exit 55
}

printDupes(){

	local_array=("${@}")
	
	e_warning "Dupes:"

	for index in ${!local_array[*]}
	do
		e_debug "${local_array[$index]}"
	done
}

# disappointing bit of code repetition here
# could be refactored
perlRandom(){

	declare -a moreDupes=()
	
	local_dupes=("${@}")

	e_header "Renaming ${#local_dupes[@]} dupe[s] with Perl"

	for index in ${!local_dupes[*]}
	do
		newName=$(perl -e '@chars = ("A".."Z", "a".."z", 0 .. 9); $rand .= $chars[rand @chars] for 1..5; print $rand;')
		e_debug "renaming ${local_dupes[$index]} to $newName.$ext"
		# if the new file already exists, add to dupes array
		# mv -nv means no overwriting and be verbose so we can match the output
		if [[ $(mv -nv "${local_dupes[$index]}" $newName.$ext | tail -n1) =~ overwritten$ ]]; then 
			moreDupes=("${moreDupes[@]:+${moreDupes[@]}}" "${local_dupes[$index]}" )
			e_warning "Dupe, not renaming"
		fi
	done

	#echo "foo ${moreDupes[@]}" # this fails if there are no more dupes moreDupes[@]: unbound variable
	count=${#moreDupes[@]} # but this is OK if moreDupes[@] is not set .. weird

	if [ $count -gt 0 ]; then
		e_debug "More dupes"
		printDupes "${moreDupes[@]:+${moreDupes[@]}}"
		perlRandom "${moreDupes[@]:+${moreDupes[@]}}"
	else
		e_success "All files renamed"
		exit 0
	fi
}

renameDupes(){
	
	declare -a moreDupes=()
	
	local_dupes=("${@}")

	e_header "Renaming ${#local_dupes[@]} dupe[s] with $shasumCmd"

	for index in ${!local_dupes[*]}
	do
		shahash=$($shasumCmd  "${local_dupes[$index]}" | awk '{ print $1}'); 

		newName=$(echo "$shahash" | cut -c -5)
		e_debug "renaming ${local_dupes[$index]} to $newName.$ext"
		# if the new file already exists, add to dupes array
		# mv -nv means no overwriting and be verbose so we can match the output
		if [[ $(mv -nv "${local_dupes[$index]}" $newName.$ext | tail -n1) =~ overwritten$ ]]; then 
			moreDupes=("${moreDupes[@]:+${moreDupes[@]}}" "${local_dupes[$index]}" )
			e_warning "Dupe, not renaming"
		fi
	done

	count=${#moreDupes[@]}

	if [ $count -gt 0 ]; then
		e_debug "More dupes"
		printDupes "${moreDupes[@]:+${moreDupes[@]}}"
		let "loopCount += 1"
		if [ $loopCount -gt 4 ]; then
			e_error "More dupes left. Trying Perl."
			perlRandom "${moreDupes[@]:+${moreDupes[@]}}"
		else
			shasumCmd="shasum -a ${shaOps[$loopCount]}"
			renameDupes "${moreDupes[@]:+${moreDupes[@]}}"
		fi
	else
		e_success "All files renamed"
		exit 0
	fi
}

# default extension
ext="png"

# quick arg check
if [ $# -eq 1 -a "${1:-unset}" = '--' ] || [ $# -gt 4 ]; then
	usage
fi

extOpt=""
prepOpt=""
extArg=0
prepArg=0

for opt in "$@"
do
    case $opt in
        -e ) extOpt="${2:-}"; extArg=1; shift ;; 
        -p ) prepOpt="prepSampleFiles ${2:-}"; prepArg=1; shift ;;
        -h | --help) usage ;;
        -*|--*) e_warning "Warning: invalid option $opt"  && usage;;
		* ) shift;;
    esac
done

if [ $extArg -eq 1 ]; then
	if [ -z "$extOpt" ]; then
		e_error "-e must have an argument. e.g. png"
		usage
	fi
fi

# must set ext first
if [ -n "$extOpt" ]; then
	#e_debug "extOpt is $extOpt"
	ext="$extOpt"
fi

if [ -n "$prepOpt" ]; then
	#e_debug "prepOpt is $prepOpt"
	eval "$prepOpt"
fi

# if no bad options, then we get to here, i.e. no options
e_header "Starting rename..."

# array to capture  dupes
declare -a dupes=()

# file listing should be case-insensitive
for file in $(shopt -s nocaseglob; ls *.$ext); 
do 
	mdhash=$(md5 -q "$file"); 
	newName=$(echo "$mdhash" | cut -c -5)
	e_debug "renaming $file to $newName.$ext"
	# if the new file already exists, add to dupes array
	# mv -nv means no overwriting and be verbose so we can match the output
	if [[ $(mv -nv $file $newName.$ext | tail -n1) =~ overwritten$ ]]; then 
		e_warning "Dupe, not renaming"
		# the :+ operator is param expansion
		# to get around the unbound variable error when array is empty
		# see http://cloud.zoooot.com/Q3V4
		dupes=("${dupes[@]:+${dupes[@]}}" "$file" )
	fi
done

# counter to change the shasum args if needed
loopCount=0

# shasum args and command
# used for renaming dupes
declare -a shaOps=(1 224 256 384 512)
shasumCmd="shasum -a ${shaOps[$loopCount]}"

# do we have any dupes?
count=${#dupes[@]} # but this is OK if dupes[@] is not set - no unbound variable error .. weird

if [ $count -gt 0 ]; then
	printDupes "${dupes[@]:+${dupes[@]}}"
	renameDupes "${dupes[@]:+${dupes[@]}}"
else
	e_success "All files renamed"
fi

exit 0