#!/usr/bin/perl

use strict;
use warnings;

use Net::SSH;

open IN,  "<hosts.txt" or die "Can't open hosts.txt";

 while(<IN>) {
  chomp;


    ssh_cmd('user@hostname', $command);
    ssh_cmd( {
    user => 'user',
    host => 'host.name',
    command => 'command',
    args => [ '-arg1', '-arg2' ],
    stdin_string => "string\n",
  } );