When developing scripts, the following can save a lot of time switching between terminal windows to re-run your script after making changes.
Install the package
inotify-tools in using your Linux package manager, then you can use the
inotifywait command to watch a file for changes and execute a command when the file is updated.
while inotifywait -e close_write <path_to_script>; do <command_to_run_script>; done