Tip 16: Fast command history in bash
From Vlsiwiki
Run the last command again:
!!
Run command 423 in your history buffer (type history to see the list):
!423
Run the last command that starts with grep:
!grep
Run the last command but substitute the first occurence of arg1 with arg2:
^arg1^arg2
Run the last command but substitute ALL occurences of arg1 with arg2:
!:gs/arg1/arg2/