Scripts can contain the first line as a comment (starting with #)
but having special meaning (second character is !) and this tells
the operating system which program should interpret the rest
of the script, if not the default one that is reading it in now.

Programs that might be seen as interpreters include:
    /bin/bash
    /bin/ash
    /bin/zsh
    /bin/sh
    /usr/bin/perl
    /usr/bin/tcl
    /bin/sed -f
    /usr/awk -f