History Interaction
Word Designators
An event designator is a reference to a command line entry in the history list.
!
 | 
    
Start a history substitution, except when followed by a space, tab,
the end of the line, `  | 
!n
 | 
    Refer to command line n.  | 
!-n
 | 
    Refer to the command n lines back.  | 
!!
 | 
    
Refer to the previous command.  This is a synonym for `  | 
!string
 | 
    Refer to the most recent command starting with string.  | 
!?string[?]
 | 
    
Refer to the most recent command containing string.  The trailing
`  | 
^string1^string2^
 | 
    
Quick Substitution.  Repeat the last command, replacing string1
with string2.  Equivalent to
  | 
!#
 | 
    The entire command line typed so far.  |