#!/usr/bin/perl -w
# Description: Fool a process into
# thinking that STDOUT is a terminal, when in fact
# it may be a file or a pipe. This can be useful
# with programs like ps and w on linux... which
# will trunc their output to the width of the
# terminal, and, if they cannot detect the terminal
# width, use a default 80 columns. Wouldn't it be
# nice to say "ps -aux | grep etcshadow", and get
# output that looks like when you just say "ps
# -aux"? Well, that's the idea.

#try ./pseudotty "xterm -e top"
#or  ./pseudotty top

use warnings;
use strict; 
use IO::Pty; 

die "usage: ptyexec command [args]\n" unless @ARGV;

my $pty = IO::Pty->new; 
my $slave = $pty->slave;
open TTY,"/dev/tty" or die "not connected to a terminal\n"; 
$pty->clone_winsize_from(\*TTY);
close TTY;

my $pid = fork(); die "bad fork: $!\n" unless defined $pid; 
if (!$pid) {
#  $slave->close();
  open STDOUT,">&=".$pty->fileno() or die $!;
  exec @ARGV;
}else{
  $pty->close();
     while (defined (my $line = <$slave>)) {
       print $line;
     }
}

#cleanup pty for next run
$pty->close();
[download]

#!/usr/bin/perl
use IO::Handle;
use IO::Pty;

sub do_cmd() {
    my $pty = new IO::Pty;
    defined( my $child = fork ) or die "Can't fork: $!";
     if ($child){
          $pty->close_slave(); #needed to close
          return $pty;
    }
    

    POSIX::setsid();
    my $slave = $pty->slave;
    close($pty);
    STDOUT->fdopen( $slave, '>' ) || die $!;
    STDERR->fdopen( \*STDOUT, '>' ) || die $!;
    system("echo This is stdout output from an external program");
    exit 0;
}

my $fh = do_cmd();
while (<$fh>) { print; }
[download]

Notice 'top' won't run, and 'ps' will only sender it's header.

#!/usr/bin/perl 
use warnings;
use strict;
use IPC::Open3;

$|=1;

#my $pid=open3(\*IN,\*OUT,\*ERR,'/bin/bash');
my $pid=open3(\*IN,\*OUT,0,'/bin/bash');
# set \*ERR to 0 to send STDERR to STDOUT

my $cmd = 'date';

#my $cmd = 'ps auxww';
#my $cmd = 'top';

#send cmd to bash
print IN "$cmd\n";

# won't work with 'top' or 'ps'
#print IN "l";
#print IN "m";
#print IN "t";
#print IN "\n";
#getresult

my $result = <OUT>;
print $result;
[download]