Chances are good the command you used is stored away in a file called
.bash_history. By default, this file stores away
the last 500 commands you typed at the shell prompt.
You can glimpse the history of your commands by typing
history at the shell prompt -- but the results will
speed by quickly.
Another way you can view .bash_history is with a
pager such as less,
by typing less .bash_history at the shell
prompt. To move forward a screen, press the Spacebar;
to move back a screen, press the B key, and to quit,
press Q.
But paging through to find a command can be tedious. A useful
alternative is to search the file for keywords using
grep, a powerful search utility.
If you can recall part of any command you'd typed at the shell prompt,
and if that command is still in .bash_history,
you can find it fast by piping the results of
the history command through the utility called
grep.
Let's say you'd been reading the man page the day before, but can't
recall its name. To search for the command, then, type:
In no time, you'll see all of the commands you'd typed which have the
word man in them -- both the relevant and
irrelevant.
There are plenty of ways to make use of command history. For other
tips and tricks, see the section called Tips on Using Command History