A slight change lets me get all keys for any array of hashes. I added the sort just for fun.

use strict;
use warnings;

my $people = [
              {
                'firstname' => ' InReach',
                'companyid' => 1042,
                'type' => 'client',
                'lastname' => 'IT Solutions',
                'id' => 1498,
                'companyname' => 'InReach IT Solutions'
              },
              {
                'firstname' => ' Neil',
                'companyid' => 1589,
                'type' => 'client',
                'lastname' => 'Ssmith',
                'id' => 3132,
                'companyname' => 'White Staffing Management'
              },
              {
                'firstname' => 'Zeeshan',
                'companyid' => 1867,
                'type' => 'client',
                'lastname' => 'Jones',
                'id' => 4174,
                'companyname' => 'Staff247'
              },
              {
                'firstname' => 'Alex',
                'companyid' => 1867,
                'type' => 'client',
                'lastname' => 'Jones',
                'id' => 4175,
                'companyname' => 'Staff248'
              },
];

foreach my $hash (@$people){
    print_hash ($hash);
}

print '*'x79, "\n";

#sort by lastname then firstname
foreach my $hash (sort { $a->{lastname} cmp $b->{lastname} or $a->{fir
+stname} cmp $b->{firstname} } @$people) {
    print_hash ($hash);
}

sub print_hash {
    my $hr = shift;
    print "\n";
    foreach my $key (keys %$hr){
        printf "%11s: %s\n", $key, $hr->{$key};
    }
}
[download]