The history command lists the recent history of commands that have been run by the shell. Sometimes it can be useful for a user to see commands that have been run in the past. For example, to remember the specific command line arguments they used to a program. It also allows a user to re-execute commands with a special shorthand notation to re-run a specific command from the shell’s history.

Here is an example run of the history command:

This example shows a series of a few commands run in the shell’s recent history. With each command in the history is a number indicating its position in the history and the time the command was started. The most recently run command was the 43nd command, history. To re-run a command from the history, you can use ! followed by the number of the command, and !! runs the most recent previous command again. This is particularly useful for easily re-running commands that have a long list of command line arguments. For example, to re-run command 37 from the history (echo "hi Sam"), a user just needs to type !37 at the shell prompt:

Note that !37 does not show up in the history, but that command number 44 from the history lists the same command line as command line 37, the one that was re-run by entering 37!.