Commands using return

allows command to use switches

Shell function; returns 0 if the port is up, 1 otherwise (check $? after executing).

First parameter: IP address/hostname

Second parameter: port number

There is no error checking for the input parameters.

ksh's version of cd has an optional syntax where you can type "cd old new" and it will replace "old" with "new" in your current directory and take you there. This is very handy when you have a parallel directory structure, like source and object directories. As suggested, you can just type cd ${PWD/old/new} to get this in bash, but this function in your .bashrc will let you type the ksh cd syntax and avoid typing the special characters while preserving other cd functionality.

This function is used to set environmental variables from a list of alternatives depending on what's installed on the system. It returns the first program found in the list.

Example usage:

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This function returns TRUE if the application supports tcp-wrapping or FALSE if not by reading the shared libraries used by this application.

This command will automate the creation of ESSIDs and batch processing in pyrit. Give it a list of WPA/WPA2 access points you're targeting and it'll import those ESSIDs and pre-compute the potential password hashes for you, assuming you've got a list of passwords already imported using:

Once the command finishes, point pyrit to your packet capture containing a handshake with the attack_db module. Game over.

to test android app

I've tried all of the screen recorders available for Linux and this is easily the best. xvidcap segfaults; VNC is too much hassle. There are alternatives of this command already here that I am just too lazy to reply to. Messing with the frames per second option, -r, 25 seems to be the best. Any lower and the video will look like a flipbook, if it records at all - -r 10 won't - any faster is the same, oddly enough.

Edit: CLF doesn't like my long command to add audio, so here it is in the description.

Especially for sysadmins when they don't want to waste time to add -p flag on the N processes of a processname.

In the old school, you did ;

and typing strace -f -p 456 -p 678 -p 974...

You can add -f argument to the function. That way, the function will deal with pgrep to match the command-line.

Example :

See more details at http://blog.amit-agarwal.co.in/2008/12/01/get-you-ip-address-like-whatismyipcom/

It is not easy to make perl give a segfault, but this does it. This is a known issue but apparently not easy to fix. This is completely useless except for showing people that perl is not bullet-proof.

Useful in while and if statements

This runs a command continuously, restarting it if it exits. Sort of a poor man's daemontools. Useful for running servers from the command line instead of inittab.