How to get Previous commands quickly in Ubuntu / Debian Linux

How to get Previous commands quickly in Ubuntu / Debian Linux

1.   You can use the up arrow to view the previous command 
2.   Type !! and press enter for the previous command
3.   Type !-1 and press enter for the previous command    
4.   Press Control+P will also display the previous command

How to Disable Bash History Temporarily in Ubunu / Debian Linux

How to Disable Bash History Temporarily in Ubunu / Debian Linux


 Some times we want to use password as command line argument. Storing your password in .bash_history file  is not a good idea.

use the following command

$  unset HISTFILE


it is only for current session.