what is git rebase

Shell
$ git checkout experiment
$ git rebase master
First, rewinding head to replay your work on top of it...
Applying: added staged commandthe rebase command integrates changes from one branch into
another. It is an alternative to the better known "merge" 
command. Most visibly, rebase differs from merge by rewriting
the commit history in order to produce a straight,
linear succession of commits.
Source

Also in Shell: