A Perl "Program" is simply a text file containing valid Perl
commands.
To run a Perl program, simply pass the name of the text file to
the Perl interpreter.
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.
Unix Example:
$ # First let me show you the contents of the file
$ cat helloworld.perl
print "Hello World\n";
$ # Now lets run it and get a look at the output
$ perl helloworld.perl
Hello World