Linux - Script (Shebang)

Script in Linux:

• can be written in many language
• does not need an extension
• must be given the execution permission

#!/bin/bash 
or
#!/usr/bin/env perl

where the first line called the shebang define the interpreter to run.

• the # is the command
• the exclamation mark (“!”) is affectionately called “bang”
• /bin/bash the path to the interpreter.
• env start a new script without environment variable

The interpreter is not limited to bash. Scripts can be written in an other language such as:

• Csh Shell

#!/bin/csh

• Python,

#!/bin/python

• Perl

#!/bin/perl

• Rscript Rscript

#!/usr/bin/Rscript

• Ruby, PHP, etc, etc.

The shebang is a kernel required syntax (not mandatory from the shell prespective)