Normally I'd just have the daemon print the command line it is called with to a specific file and have the script read that file.

If for some reason that doesn't work and you happen to be on Linux, you can get the exact command line a process was called with by examining the /proc/<process id>/cmdline file. So, for example, the below code will print out the command line:

#!/usr/bin/perl

use warnings;
use strict;

open (my $fh,"<","/proc/$$/cmdline") or die "Can't access proc file: $
+!";
my $line = (<$fh>);
close $fh or die "Can't close proc file: $!";

my @cmdline = split("\0",$line);

print join(" ",@cmdline)."\n";
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