Posts tagged Linux

Linux Startup Scripts

Nov 17th

Posted by PB in OS

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The following scripts are run by bash if the –noprofile option is not used with the shell:

/etc/profile – This script file is run first for all users during the login process
$HOME/.bash_profile – This script file is run for individual user’s customized setup
$HOME/.bash_login – If the .bash_profile above does not exist, this file is run
$HOME/.profile – This script file is run if $HOME/.bash_profile and .bash_login don’t exist
/etc/bashrc – On my Redhat system, this file is run by $HOME/.bashrc.
$HOME/.bash_logout – Run when the user logs off the system.

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Linux – I installed the x86_64 version, so why do I have i386 packages

Nov 4th

Posted by PB in OS

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In my case CentOS follows the upstream source and the x86_64 installation by default will install iX86 32-bit packages on a 64-bit installation for compatibility purposes. Many server system administrators and some desktop users want a pure 64-bit system and want to remove 32-bit packages. This can be accomplished as follows:

yum remove \*.i\?86

To keep 32-bit packages from being installed in future updates, edit your /etc/yum.conf

vi /etc/yum.conf

and add the line:

exclude = *.i?86
Note:

Be aware that 32-bit applications, including some browser plugins that may only be available in 32-bit versions, will no longer work after this procedure so be carefully.

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Copy directory structure without content.

Sep 16th

Posted by PB in Commands

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Handy command to run if you need the directory structure replicated without the content.

To demonstrate I am going to create an example directory:

mkdir /new/destination/root/

The go into the root directory you want to replicate:

cd /source/root/

and type:

find * -type d -exec mkdir /new/destination/root/\{\} \;

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crontab

Sep 15th

Posted by PB in Commands

1 comment


What is crontab:

Cron is a time-based job scheduler in Unix-like computer operating systems. The name cron comes from the word chronos, Greek for time. Cron enables users to schedule jobs (commands or shell scripts) to run periodically at certain times or dates. It is commonly used to automate system maintenance or administration,

Cron is driven by a crontab, a configuration file that specifies shell commands to run periodically on a given schedule. Each line of a crontab file represents a job and is composed of a CRON expression, followed by a shell command to execute.

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Uptime command

Jul 15th

Posted by PB in Commands

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The uptime command produces a single line of output that shows the current time, how long the system has been running (in minutes) since it was booted up, how many user sessions are currently open and the load averages.

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Listing cron jobs

Jun 30th

Posted by PB in OS

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If you have root access to a server and you have a large number of domains with cron jobs the easiest way to list them all is:

cd /var/spool/cron
cat *

Your output might look somehting like this:

29	2	25	*	*	python /var/www/vhosts/thesupportsystem.com/httpdocs/sitemap/sitemap_gen.py --config=/var/www/vhosts/thesupportsystem.com/httpdocs/sitemap/config.xml

*/5	*	*	*	*	php -f /var/www/vhosts/thesupportsystem.co.uk/httpdocs/email_marketer/admin/cron/cron.php

0	*	*	*	*	wget -O - -q -t 1 http://www.thesupportsystem.com/cron.php
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Linux Searching All Files For A String (Recursively)

Feb 18th

Posted by PB in OS

1 comment

Linux Searching All Files For A String (Recursively)

You can use the grep or find command to search recursivley for a string

Basic grep command

grep -ri "STRING" .
Options
Option Description
-r recursive
-i ignore case

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