This page is about the creation of Script in Linux.
They
#!/bin/bash
or
#!/usr/bin/env perl
where the first line called the shebang define the interpreter to run.
The interpreter is not limited to bash. Scripts can be written in an other language such as:
#!/usr/bin/env bash
#!/bin/csh
#!/bin/python
#!/bin/perl
#!/usr/bin/Rscript
The shebang is a kernel required syntax (not mandatory from the shell prespective)
According to the FHS, the script may be located: