With no options, display the command history list with line numbers. Lines listed with a * have been modified. An argument of n lists only the last n lines. If filename is supplied, it is used as the name of the history file; if not, the value of HISTFILE is used. Options, if supplied, have the following meanings:

-a   Append the ``new'' history  lines  (history  lines
     entered  since  the  beginning of the current bash
     session) to the history file.
-n   Read the history lines not already read  from  the
     history file into the current history list.  These
     are lines appended to the history file  since  the
     beginning of the current bash session.
-r   Read the contents of the history file and use them
     as the current history.
-w   Write the current history  to  the  history  file,
     overwriting the history file's contents.
-c   Clear  the  history  list  by  deleting  all   the
     entries.

documented on: Wed 03-24-99 09:59:08