When you type “hash” on a Linux system, you could get one of two very different responses depending on the shell you are using.
If you are using bash or a related shell such as ksh, you should see a list of the commands that you have used since your terminal session began, sometimes with a count of how many times each command was used. This can be more useful than using the history command if you just want to see your very recent command activity, but the hash command is not a single executable. Instead, it relies on your shell.
hash in bash
Here’s an example of the hash command run in bash: