if you want to save that shell script to a file for easy running, type this from a terminal:
then press enter, then type as the first line, then paste the above script in entirity, then press enter for a new line and press CTRL+D to end the file.

Now make it executable:
and now whenever you want to run it, type:
that line starts with a dot and assumes you did all of the above in your home directory, which is the default working directory when you open a terminal.