Find Some Commands Fast

Q: Locating Previously Used Commands

I was looking at a man page yesterday, but I can't remember the name of the command I was reading about, and I didn't write it down. How do I get the man page back?

A: Seaching .bash_history .

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:

history | grep man


		

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