With the help of user ikegami over at stackoverflow. The following solutions
works.
[-
use warnings;
use strict;
use IPC::Open3;
use POSIX;
$http_headers_out{'Content-Type'} = "text/plain";
my $cmd = 'ls';
open(my $fh, '>', '/dev/null') or die $!;
dup2(fileno($fh), 1) or die $! if fileno($fh) != 1;
local *STDOUT;
open(STDOUT, '>&=', 1) or die $!;
my $pid = open3(*HIS_IN, *HIS_OUT, *HIS_ERR, $cmd);
close(HIS_IN); # give end of file to kid, or feed him
my @outlines = <HIS_OUT>; # read till EOF
my @errlines = <HIS_ERR>; # XXX: block potential if massive
print OUT "STDOUT: ", @outlines, "\n";
print OUT "STDERR: ", @errlines, "\n";
waitpid( $pid, 0 );
my $child_exit_status = $? >> 8;
print OUT "child_exit_status: $child_exit_status\n";
-]
