($result, $exitcode) = run_w_progress(1, 'for i in `seq -w 4`; do sleep 3; /bin/echo $i; done');

##</code><code>##

Result:
1
2
3
4

Exitcode:0
finishing ...

##</code><code>##

($result, $exitcode) = run_w_progress(1, '/bin/echo -e "foo\nbar"');

##</code><code>##

Result:
foo

Exitcode:0
finishing ...

##</code><code>##

#!/usr/bin/perl                                  
 
use strict;
use warnings;
use POSIX ":sys_wait_h";
use IO::Select;         
use IO::Handle;         

my ($result, $exitcode) = run_w_progress(1, 'for i in `seq -w 4`; do sleep 3; /bin/echo $i; done');
print "Result:\n",$result,"\nExitcode:",$exitcode,"\n";                                            

($result, $exitcode) = run_w_progress(1, '/bin/echo -e "foo\nbar"');
print "Result:\n",$result,"\nExitcode:",$exitcode,"\n";             

sub run_w_progress {
        my ($sleep, $cmd) = @_;
        my($reader, $writer);  
        pipe $reader, $writer;
        my($reader2, $writer2);
        pipe $reader2, $writer2;
        $writer->autoflush(1);
        $writer2->autoflush(1);
        my @watch = qw(| / - + \ | / - \ |);
        my $pos = 0;
        $|++;
        if ( fork()) {
                my $kid;
                my $output = '';
                my $exitval;
                my $c=0;
                my $handles = IO::Select->new();
                $handles->add($reader, $reader2);
                do {
                        sleep $sleep;
                        my @fhs;
                        while (@fhs = $handles->can_read(0)) {
                                for my $fh (@fhs){
                                        if (fileno($fh) == fileno($reader)) {
                                                my $line = scalar <$reader>;
                                                        $output .= $line;
                                        }
                                        else {
                                                        $exitval = scalar <$reader2>;
                                                        chomp $exitval;
                                        }

                                }
                        }
                        print "\r",'|'x$pos,$watch[$c++];
                        if ($c == 10) {
                                $c=0;
                                $pos++;
                        }
                        $kid = waitpid(-1, WNOHANG);
                } until $kid > 0;
                print "|\n";
                return ($output, $exitval);
        }
        else {
                open(my $pipe, '-|', $cmd);
                while (<$pipe>) {
                        # pass output line to parent
                        print $writer $_;
                }
                close $pipe;
                close $writer;
                # pass exit value to parent 
                print $writer2 $?>>8, "\n";
                close $writer2;
                exit 0;
        }
}

print "finishing ...\n";