It doesn't even print any errors. Any thoughts?

I'm not sure why you chose IO::Pipe to run this, but the IO::Pipe docs show

$pipe->reader(qw(ls -l));
 while(<$pipe>) {
                 print   ...
               }
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I would think that IPC::Open3 would be more straightforward. Like this example which shows how to grab STDERR too.

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

my $pid = open3(\*WRITE, \*READ,\*ERROR,"/bin/bash");

my $sel = new IO::Select();

$sel->add(\*READ);
$sel->add(\*ERROR);

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

while(1){

 print "Enter command\n";
 chomp(my $query = <STDIN>);
 
 #send query to bash
 print WRITE "$query\n";

 foreach my $h ($sel->can_read)
 {
   my $buf = '';
   if ($h eq \*ERROR)
   {
     sysread(ERROR,$buf,4096);
     if($buf){print "ERROR-> $buf\n"}
   }
   else
   {
     sysread(READ,$buf,4096);
     if($buf){print "$query = $buf\n"}
   }
 }
}

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