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Edit the /etc/sudoers config file the right way.
'visudo' is installed by default on most Unix-like systems. If not installed, you can get it from the 'sudo' package. 'visudo' will use the text editor found in your $EDITOR variable, whether it's vi, vim, emacs, nano or gedit. After making changes to the /etc/sudoers file, visudo will check for syntax errors, and notify you of them. This is better than 'vi /etc/sudoers', because of this capability. Rule #1 of system administration- if there is a tool that exists for editing config files, use the tool.

set history file length
set how many commands to keep in history Default is 500 Saved in /home/$USER/.bash_history Add this to /home/$USER/.bashrc HISTFILESIZE=1000000000 HISTSIZE=1000000

Create a backdoor on a machine to allow remote connection to bash
My netcat (nc-1.84-10.fc6) doesn't have the -e option, so I have to do it like this. Of course, instead of bash, you can use any executable, including scripts.

seq (argc=2) for FreeBSD

Eavesdrop on your system
This command takes a snapshot of the open files for a PID 1234 then waits 10 seconds and takes another snapshot of the same PID, it then displays the difference between each snapshot to give you an insight into what the application is doing.

Route outbound SMTP connections through a addtional IP address rather than your primary

Get your current Public IP

ASCII webcam live stream video using mplayer
Mplayer starts a webcam capture using ASCII art. Only mplayer required

Convert ascii string to hex

Rename files in batch


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