Print a process tree on Solaris

pstree

#! /usr/bin/perl
##
## Print a process tree on Solaris
##

use strict;
use warnings;

my $l; # process list
my $r; # process relations

open PS, "ps -e -o user= -o pid= -o ppid= -o args= |";
while (<PS>)
{
  chomp;
  my ($user, $pid, $ppid, $args) = split(" ", $_, 4);
  $l->{$pid} = {user=>$user, args=>$args};
  $r->{$ppid}->{$pid} = 1;
}
close PS;

sub print_pid {
  my ($i, $p) = @_; # indent level, pid
  printf "%8s %5s %*s%s\n", $l->{$p}->{user}, $p, $i*2, '', $l->{$p}->{args};
  if (exists $r->{$p}) {
    for (sort keys %{$r->{$p}}) {
      print_pid ($i + 1, $_) unless $_ eq $p;
    }
  }
}

# On Solaris the first process has not the pid 1 but its own pid
# equals to the parent pid.

my ($a) = grep { exists $r->{$_}->{$_} } keys %$l;

print_pid 0, $a;