#!/usr/bin/perl
use strict;
use warnings;
use Net::SSH2;
use Date::Manip;

my $datestr = ParseDate("now");
my $dateHumanReadable = UnixDate($datestr, "Date: %T on %b %e, %Y.");

#get ip’s
#open file
my $ipFile = "ips2.txt";
open(my $FH, '<', $ipFile)
    or die ("Unable to open file '".$ipFile."': $!");
# read file into an array
chomp(my @data = <$FH>);
close $FH
    or warn "Unable to close file '".$ipFile."': $!";

my $ssh2 = Net::SSH2->new();

foreach my $sw (@data) {
    $ssh2->connect($sw, 22) or $ssh2->die_with_error; # port default 22 update if you use other port

    $ssh2->auth( publickey => "/home/user/.ssh/id_rsa"); # ssh key authentication, update for user and password

    my $chan = $ssh2->channel()
	or $ssh2->die_with_error;

    $chan->blocking(1);

    $chan->exec("ls -la /home/user/Monks/Foo")
	or $ssh2->die_with_error;

    my $stdoutFileName = "stdout-$sw.txt";
    open(my $fhStdOut, '>', $stdoutFileName)
	or die "Could not open file '".$stdoutFileName."' $!";

    print $fhStdOut $dateHumanReadable;

    while (<$chan>){
	print $fhStdOut $_;
    }

    close $fhStdOut
	or warn "Unable to close file '".$stdoutFileName."': $!";

    my $stderrFileName = "stderr-$sw.txt";
    open(my $fhStdErr, '>', $stderrFileName)
	or die "Could not open file '".$stderrFileName."' $!";

    print $fhStdErr "exit status: " . $chan->exit_status . "\n";

    close $fhStdErr
	or warn "Unable to close file '".$stderrFileName."': $!";

    $ssh2->disconnect();
}

__END__

$ time perl test.pl

real	0m0.368s
user	0m0.127s
sys	0m0.008s

$ cat stdout-127.0.0.1.txt
Date: 13:45:44 on Aug  8, 2018.total 16
drwxrwxr-x  2 user user 4096 Feb 28 21:10 .
drwxrwxr-x 14 user user 4096 Aug  8 13:45 ..
-rw-rw-r--  1 user user  263 Feb 28 21:10 Bar.pm
-rw-rw-r--  1 user user  184 Jan 30  2018 Bar.pm~

$ cat stderr-127.0.0.1.txt
exit status: 0