Automating Perl Execution

• A standard Unix trick is to put the path for the interpreter associated with a particular file in the first line with a "pseudo" comment, and change the file to have execute permissions.
• Then to run a Perl program, simply type the path to the file containing your Perl commands.
• The "normal" place for the Perl interpreter program is /usr/bin/perl, but it could be anywhere. It is probably already in your path, so you only have to type "perl". Otherwise, ask your system administrator. It is exceptionally rare for a Unix system to not have Perl installed somewhere.

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• Unix Example:
  

   
  $ # Note we have now added another line to the file
  $ cat helloworld.perl
  #!/usr/bin/perl
  print "Hello World\n";
  $ # Now give it execute permission (only necessary once)
  $ chmod +x helloworld.perl
  $ # Now lets run it and get a look at the output
  $ ./helloworld.perl
  Hello World