Dara Ardalan D4R4

IT Administrator

D4R4 / linux_find_replace

Created April 1, 2019 07:09

find and replace str in filename in a directory recursively

find . -name '*StR1*' -type f -exec bash -c 'mv "$1" "${1/StR1/StR2}"' -- {} \;

D4R4 / snmpd_centos

Last active May 14, 2019 03:11

SNMPD on CentOS

	yum -y install net-snmp net-snmp-utils

	firewall-cmd --zone=public --permanent --add-port=161/tcp
	firewall-cmd --zone=public --permanent --add-port=161/udp

D4R4 / mysql_replace-text.sql

Created April 1, 2019 07:49

replace text in mysql text field

	UPDATE
	table_name
	SET
	column_name = REPLACE(column_name, 'text to find', 'text to replace with')
	WHERE
	column_name LIKE '%text to find%';

D4R4 / mysql_replace_from_another_table.sql

Created April 1, 2019 10:59

replace value with other column index as relation between tables

	UPDATE prods
	INNER JOIN cat_key ON (prods.cat = cat_key.name)
	SET prods.cat = cat_key.id

D4R4 / reset_rx_counter.sh

Last active September 5, 2019 07:40

The script causes a reset in interface TX Packet bytes transfered which should be applied monthly to keep a correct billing record

sudo -- sh -c  'ifdown eth0 ; modprobe -r vmxnet3; modprobe vmxnet3 ; ifup eth0'

D4R4 / python_ip.py

Last active May 12, 2019 15:29

Python functions to mess around with IP Addresses and ranges, useful to prase data from directories like RIPE or etc.

	import socket,struct

	def makeMask(n):
	"return a mask of n bits as a long integer"
	return (2L<<n-1) - 1

	def dottedQuadToNum(ip):
	"convert decimal dotted quad string to long integer"
	return struct.unpack('L',socket.inet_aton(ip))[0]

D4R4 / epel-release

Created May 8, 2019 15:56

Sometimes, in the CentOS 7 Live you get yum Repo erros after you install epel-release (for mounting VMDKs for example)

	1. You should upgrade CURL
	2. you better upgrade ca-certificates
	3. install epel-release
	4. install epel package

D4R4 / escape_space

Created May 8, 2019 16:35

Escape space in SCP command path

	scp user@host:/path/to/directory\\\ with\\\ spaces/file ~/Downloads

D4R4 / rsync_cron

Created May 11, 2019 20:29

Rsync with remote site with cron consideration

pgrep -cx rsync ||  sshpass -p 'P@SSW0RD' rsync -avzP -e "ssh -p 4532" root@HOSTNAME:/var/www/dataroot/html/media /var/www/html

D4R4 / LVM_physical

Created May 14, 2019 03:11

extend a partition with a LVM and the contained physical volume and logical volume

	1. Resize the partition (again, you can do this with the system running). GParted is easy to use and supports resizing.
	You can also use a lower level tool such as fdisk. But you'll have to delete the partition and recreate it. Just make sure when doing so that the new partition starts at the exact same location.
	2. partprobe or Reboot. Since the partition table was modified on the running system, it won't take effect until a reboot.
	3. Run pvresize /dev/sdXY to have LVM pick up the new space.
	4. Resize the logical volume with lvextend. If you want to use the whole thing, lvextend -r -l +100%FREE /dev/VGNAME/LVNAME. The -r will resize the filesystem as well.
	Though I always recommend against using the entire volume group. You never know what you'll need in the future. You can always expand later, you can't shrink.