Assuming you don't want to explicit pass the script name, you can do what you want using caller.

Update: as per chromatic's comment, I should have queried as to how you are calling the other script. If you are invoking the OS (through backticks, system(), etc.) then Joost is right. A simple solution in that case would be to repackage hello.pl as a package, which would then allow you to directly call the hello subroutines and use the caller method as I suggested before.

Some sample code (obviously I don't know how your files are set up):

#!/usr/bin/perl -w

use strict;
use warnings;
use Hello;

hello;
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#!/usr/bin/perl -w
package Hello;
use strict;
use warnings;
use Exporter;
our @ISA = qw(Exporter);
our @EXPORT = qw(hello);

sub hello {
    print "hello\n";
    my @call_info = caller;
    print $call_info[1], "\n";
}


return 1;
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