If you have control over the second script make it what "Effective Perl Programming (second edition)" calls a modulino - a module that can be run as a script or used as a module. Consider:

use strict;
use warnings;

package Demo;

sub run {
    print "Hello world\n";
}


run (@ARGV) if ! caller ();

1;
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which executes the run sub when run from the command line, or can be used in another script where you can call Demo::run () to have the same effect as running it from the command line, but with the advantage that it is now trivial to pass and return data.