bash history with timestamps

This is definitely something useful!
How to attach timestamps to the history of the bash commands?
Simple:  just set (in the way you like to have your time format) the bash variable HISTTIMEFORMAT

For example to have the format: day/month/year - hours:minutes:seconds" type this:

export HISTTIMEFORMAT="%d/%m/%y - %H:%M:%S: "

and then just run history

That's it!

Source
 stackoverflow

How to change bash prompt to red when you are root

To change your bash shell prompt to red when you became root,  do the following:

• login as root
• vi ~/.bashrc
• add the this line:  export PS1='\[\e[31m\][root]\[\e[0m\] \W\$'

 That's it!

Bash: How to change recursively owner and group of files and dirs

Sometimes comes in hand to change recursively the owner and group for files in a directory. How to do this in bash?

With this command:

find /starting/path -user "original_owner"  -exec chown someuser:somegroup {} +

You can omit ":somegroup" if you don't want to change the group of the files/folder
For example to change from root to foo of foogroup in the folder /var/lol  use the command:

find /var/lol -user "root"  -exec chown foo:foogroup {} +

NOTE: You must be root to change the ownership of a root-owned file! 

Source

superuser