How To Use Bash History Commands and Expansions on a Linux VPS

Bash history is a feature that keeps a record of commands that have been executed on a Linux VPS. This can be useful when you need to re-run a command or if you need to remember a particular command that you used in the past. Bash also provides several expansion features that can help you quickly and easily reference previous commands.

Step 1: View Your Bash History

The first step is to view your Bash history. You can do this by typing the following command:

history

This will display a list of your most recent commands. Each command is preceded by a number, which you can use to reference the command in later steps.

Step 2: Re-run a Command

To re-run a command from your history, you can use the !n syntax, where n is the number of the command you want to re-run. For example, if you want to re-run the command with the number 1234, you would type:

!1234

This will re-run the command with the number 1234 from your Bash history.

Step 3: Use Command Substitution

You can use command substitution to reference the output of a previous command. To do this, you use the $(command) syntax, where command is the command you want to reference. For example, if you want to reference the output of the ls command, you would type:

echo "$(ls)"

This will print the output of the ls command to the console.

Step 4: Use History Expansion

Bash provides several expansion features that can help you quickly and easily reference previous commands. Some of the most useful history expansions are:

• !! - Re-run the previous command
• !$ - Reference the last argument of the previous command
• !:n - Reference the n-th argument of the previous command
• !^ - Reference the first argument of the previous command
• !* - Reference all arguments of the previous command

For example, if you want to reference the last argument of the previous command, you would type:

echo !$

This will print the last argument of the previous command to the console.

Conclusion

Bash history