Shebang

What is Shebang?

A shebang is the "#!" character sequence at the start of a script file that tells the operating system which interpreter should be used to run it.

For example, in a Perl script, the shebang line typically looks like this:

#!/usr/bin/perl

This line tells the operating system where the Perl executable is located - in this example, at /usr/bin/perl. The shebang must occupy the very first line of the script, and should be the only statement on that line.

Can a shebang include options?

Yes. The shebang line can include command-line "switches" after the interpreter path. For example, the following line also instructs Perl to enable warnings:

#!/usr/bin/perl -w

Is a shebang always required?

The shebang line is generally only required on Linux and UNIX systems. In some Microsoft Windows server environments it may not be needed and can be omitted, but it is best practice to always include it. Without a correct shebang line, a Perl script may fail to run.

Shebang and MIDAS

Because MIDAS is written in Perl, a correct shebang line at the top of its Perl files is important when running a self-hosted edition on a Linux or UNIX web server.