Very useful when working on production management hosts and you want to know when you ran a specific command.
Add the following to your to your ~/.bashrc.
export HISTTIMEFORMAT="%F %T "
Example of Output:
$ history
508 2016-06-22 19:26:09 history
509 2016-06-22 19:26:15 vi .bashrc
510 2016-06-22 19:26:21 ls
511 2016-06-22 19:26:23 history
