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

#interface to bash
my $pid = open3(\*WRITE, \*READ,\*ERROR,"bash");
            #if \*ERROR is false, STDERR is sent to STDOUT 

my $selread = new IO::Select();
my $selerror = new IO::Select();
$selread->add(\*READ);
$selerror->add(\*ERROR);
# may not be best use of IO::Select, but it works :-)

my($error,$answer)=('','');

while(1){

print "Enter expression for bash, i.e. date\n";
chomp(my $query = <STDIN>);

#send query to bash
print WRITE "$query\n";

#timing delay needed tp let bash output
select(undef,undef,undef,.01); 

#see which filehandles have output
if($selread->can_read(0)){print "ready->read\n"}
if($selerror->can_read(0)){print "ready->error\n"}
 
#get any error from bash
sysread(ERROR,$error,4096) if $selerror->can_read(0);
if($error){print "\e[1;31m ERROR-> $error \e[0m \n"}

#get the answer from bash
sysread(READ,$answer,4096) if $selread->can_read(0);
if($answer){print "$query = $answer\n"}

($error,$answer)=('','');
}

waitpid($pid, 1);
# It is important to waitpid on your child process,  
# otherwise zombies could be created.