Part I - Shell Tips & Tricks Clear and Disable Bash History Use the Bash inbuilt history command: Code: history -c To prevent writing of your Bash history to the history when you log out: Code: unset HISTFILE Ampersand (Background Jobs) & is a inbuild operator to fork processes. "If a command is terminated by the control operator &, the shell executes the command in the background in a subshell" Code: [root@pradeep test]# sleep 60 &  32739 The process id is stored in a special variable $! Code: [root@pradeep test]# echo $! 32739 List all background jobs Code: [root@pradeep test]# jobs + Running sleep 60 & Killing any background job Code: [root@pradeep test]# kill %1 + Terminated sleep 60 Search An Replace in vi Open a text file in vi/vim and goto command mode by pressing ECS and then ':', the search and replace command will be like, Code: %s/oldString/NewString/g You can also mention which lines should be affected by this, %s means all lines. Code: 5,10 s/oldString/NewString/g This will tell vi to make do replacing in lines 5 to 10. You may also use regex in your search expression.