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Quickly: Command history in Linux / Shell

If you are like me, doing a lot of command line in linux (Bash) shell, there are a few commands you do very often. The following commands will make your life a lot easier to quickly go back in command history.

[!!] or better yet [sudo !!] - [!!] is an alias for last run command. One of the best use of this is - Sometimes, you type a command and the shell hits you back with a root privileges required message. You dont have to copy the command and run again. just run [sudo !!]

[history] - just spits out ~/.bash_history with line numbers. A good use of this is piping it to grep to find something. The line numbers can be used to execute the command following it. Say for example, [history | grep find] lists the previous searches (okay, it also shows all commands with "find" anywhere in the line - but a filtered, smaller list). 
$history | grep find
 457  find *.wav
 462  find *.wav -exec lame --preset fast extreme '{}' '/tmp/mp3/{}' \;
 487  find *.wav -exec mp3cvbr '{}' \;

To rerun the search just type !nnn where nnn is the number of the line shown, eg: !462.

And the best one..
[CTRL+R] Dont *type* it - press control + r on your keyboard at shell prompt. It opens a prompt that will start a reverse search on history of commands. Then, Type any part of the command (or arguments) that you have done in the past, it will fill in the whole command including the arguments. Hit Enter to execute it!!
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