#!/usr/bin/perl

my $ppid = getppid();   # parent PID

my $procfile = "/proc/$ppid/cmdline";

open my $fh, "<", $procfile or die "Cannot open $procfile: $!";
my $cmdline = <$fh>;
$cmdline =~ tr/\0/ /;
close $fh;

print  "cmdline: $cmdline\n";