Have a look at IPC::Run for a robust implementation of this, or for simple uses that don't require pty emulation and you don't need to capture the output, open will do what you want. Here's a barebones look at both:
use 5.010;
use autodie;
# With basic open()
open my $sort, '|-', 'sort -n';
printf $sort "%d\n", rand 100 for 1..10;
close $sort;
# With IPC::Run
use IPC::Run qw/start finish pump/;
print "IPC::Run output:\n";
my $r = start [ 'perl' ], \my $in, \my $out, \my $err
or die "Can't start: $!";
$in .= 'print "Hello, world!\n";';
finish $r;
say $out;
die 'ERROR: $err' if length $err;
Output:
13
14
34
37
44
63
83
86
90
95
IPC::Run output:
Hello, world!
use strict; use warnings; omitted for brevity.
| 