Unix in a Nutshell, 4th Edition

Name

#!

Synopsis

    #! shell

Used as the first line of a script to invoke the named shell. Anything given on the rest of the line is passed as a single argument to the named shell. This feature is typically implemented by the kernel, but may not be supported on some older systems. Some systems have a limit of around 32 characters on the maximum length of shell. Any program that interprets input may be used for shell, such as awk or Perl. For example:

    #! /bin/tcsh 
 -f