How to use the history command in Linux

As I spend more and more time in terminal sessions, it feels like I'm continually finding new commands that make my daily tasks more efficient. The GNU history command is one that really changed my work day.

The GNU history command keeps a list of all the other commands that have been run from that terminal session, then allows you to replay or reuse those commands instead of retyping them. If you are an experienced terminal user, you know about the power of history, but for us dabblers or new sysadmin folks, history is an immediate productivity gain.

First of all, the history command isn't actually a command. You can see this for yourself by looking for the command on your system:

$ which history
which: no history in (/usr/local/bin:/usr/bin:/bin:/usr/games:/usr/local/sbin)

Your computer can't find the history command because it's a built-in keyword of your shell. Because it's written into the shell you're using, there can be some variation in how history behaves depending on whether you're using Bash, tcsh, Zsh, dash, fish, ksh, and so on. This article is based upon the Bash implementation of history, so some functions may not work in other shells. However, most of the basic functions are the same.

History 101

To see history in action, open a terminal program on your Linux installation and type:

$ history

Here's the response I got:

1  clear
2  ls -al
3  sudo dnf update -y
4  history

The history command shows a list of the commands entered since you started the session. The joy of history is that now you can replay any of them by using a command such as:

$ !3

The !3 command at the prompt tells the shell to rerun the command on line 3 of the history list. I could also access that command by entering:

$ !sudo dnf

This prompts history to search for the last command that matches the pattern you provided (in this case, that pattern is dnf) and run it.

Searching history

You can also use history to rerun the last command you entered by typing !!. By pairing it with grep, you can search for commands that match a text pattern or, by using it with tail, you can find the last few commands you executed. For example:

$ history | grep dnf
3  sudo dnf update -y
5  history | grep dnf

$ history | tail -n 3
4  history
5  history | grep dnf
6  history | tail -n 3

Another way to get to this search functionality is by typing Ctrl-R to invoke a recursive search of your command history. After typing this, the prompt changes to:

(reverse-i-search)`':

Now you can start typing a command, and matching commands will be displayed for you to execute by pressing Return or Enter.

Changing an executed command

You can also use history to rerun a command with different syntax. You can revise history with history. For example, if I want to change my previous command history | grep dnf to history | grep ssh, I can execute the following at the prompt:

$ ^dnf^ssh^

The command is rerun, but with dnf replaced by ssh. In other words, this command is run:

$ history | grep ssh

Removing history

There may come a time that you want to remove some or all the commands in your history file. If you want to delete a particular command, enter history -d <line number>. To clear the entire contents of the history file, execute history -c.

The history file is stored in a file that you can modify, as well. Bash shell users find it in their home directory as .bash_history.

Next steps

There are a number of other things that you can do with history:

• Set the size of your history buffer to a certain number of commands
• Record the date and time for each line in history
• Prevent certain commands from being recorded in history

For more information about the history command and other interesting things you can do with it, take a look at Seth Kenlon's articles about parsing history, history search modifiers, and the GNU Bash Manual.

This article was originally published in June 2018 and has been updated with additional information by the editor.