29Aug 2012 by Asim Zeeshan 1 Comment

How to find zombie processes on linux

CentOS, Linux, Tips and Tricks, Ubuntu
My NAGIOS monitor alerted me that of my dedicated server has 10 Zombie processes, how to find Zombie processes via command line on Linux especially CentOS? So it returns state (Z = Zombie) and the process id (PID) Technically, you cannot kill a zombie process since its already dead but the entry in the process table is not removed because the parent will access the result via the PID in the process table.
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27May 2012 by Asim Zeeshan No Comments

How to find specific files and send alerts

CentOS, How to, Linux, Tips and Tricks, Ubuntu
Maintaining a shared hosting server is a full time job but tools and proper checks and balances can help make this burden lot less. I manage a shared hosting server for one of my friends and numerous times the scripts that people have installed over on their websites have vulnerabilities and hackers exploit it to upload stuff that mass-email or do other nasty stuff. Luckily, most of these exploits have common patterns like files names or other signatures that make them traceable (most of the time the so called hackers are just kiddy scripts) Create a file and put this in it This is a small script that finds specific named scripts in the /home directory (mostly cPanel servers). You can put this in the crontab to do a scan…
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25May 2012 by Asim Zeeshan No Comments

How to configure repos to not overwrite base packages?

CentOS, How to, Linux
The greatest fear with adding additional and especially third party repos such as EPEL (we did a blog post on how to install EPEL earlier) is that it MAY overwrite base packages and bring the system to an unstable state. We can fix this issue by installing Yum Priorities plugin on CentOS 5: on CentOS 4 or CentOS 6: Then make sure that the plugin is enabled Now there are two ways to do it, either set HIGHEST priority to CentOS repos OR set lowest priority to other repos. This is done by adding the line In this blog post, I will set 1 as the priority (highest) for my CentOS Base repo So that it becomes Other repos do not need updating since I have assigned CentOS repos with…
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20May 2012 by Asim Zeeshan 2 Comments

Freshclam daemon not running

CentOS, How to, Linux
Normally, I have two things on every Linux box so that I know whats going on NAGIOS monitoring (nrpe) Logwatch Today, I got something in my logwatch email and it was strange because just the other day, I upgraded the clamav to latest version using epel reo. It appears that the latest version has some permission issues on the log file because when I try to run freshclam on command line I get this The solution? The solution is very simple :) just do the following and after that, run freshclam (the service that updates the virus-definition for clamav)
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28Mar 2011 by Asim Zeeshan 2 Comments

Find memory consumed by currently running processes on Linux?

CentOS, How to, Linux, OpenSource, Resources, Reviews, Tips and Tricks, Tutorials, Ubuntu, Virtual Private Server
I always had the question (when I am running plenty of scripts on a linux box as to what is eating up all the memory? Finding memory consumed by current running processes in your favorite linux distro. Luckily, I found a great Python utility (scriplet to be exact). (more…)
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