use strict;
use warnings;
use Data::Dumper;

my $command = "ps -f";
my $id = "PID";

my @ps =`$command`;
$ps[0] =~ s/^\s*//;
my @header = split /\s+/, shift @ps;
my ($posid) = grep { $header[$_] eq $id } 0..$#header;
die "$id: No such column!\n" unless defined( $posid );
splice @header, $posid, 1;
my $n = (scalar @header) - 1;

my %psdata;
while( @ps ) {
  my $row = shift @ps;
  $row =~ s/^\s*//;
  my @row = split /\s+/, $row;
  my $this_id = splice @row, $posid, 1;
  @{$psdata{$this_id}}{@header[0..$n-1]} = splice @row, 0, $n;
  $psdata{$this_id}{$header[$n]} = join " ", @row; # inaccurate as it just pastes everything together
}

print Dumper( %psdata );