The #! at the beginning of a shell script is commonly referred to as the Shebang.
The Shebang #! is usually followed by the path to the command interpreter e.g. /bin/bash or /bin/sh and an optional argument:
Any intervening white space is ignored / optional. Accordingly the following are considered equivalent:
- #! /bin/bash
*notice the subtle difference of the ignored space between the Shebang #! and the path: /bin/bash