Commands by rakibfiha (1)

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repeat a command every one second
Short method of "while x=0; do foo ; sleep 1 ; done"

Add directory to $PATH if it's not already there
Sometimes in a script you want to make sure that a directory is in the path, and add it in if it's not already there. In this example, $dir contains the new directory you want to add to the path if it's not already present. There are multiple ways to do this, but this one is a nice clean shell-internal approach. I based it on http://stackoverflow.com/a/1397020. You can also do it using tr to separate the path into lines and grep -x to look for exact matches, like this: $ if ! $(echo "$PATH" | tr ":" "\n" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://stackoverflow.com/a/5048977. Or replace the "echo | tr" part with a shell parameter expansion, like $ if ! $(echo "${PATH//:/$'\n'}" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://www.commandlinefu.com/commands/view/3209/. There are also other more regex-y ways to do it, but I find the ones listed here easiest to follow. Note some of this is specific to the bash shell.

switch case of a text file

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

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

determine if tcp port is open

execute your commands and avoid history records
$ secret_command;export HISTCONTROL= This will make "secret_command" not appear in "history" list.

Generate a quick, lengthy password

Are the two lines anagrams?
This is just a slight alternative that wraps all of #7917 in a function that can be executed

Watch active calls on an Asterisk PBX


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