CODEWITHSUNDEEP
perlssh
Rajeev
Rajeev

Reputation: 46979

perl system command execution

In the following code I need to print output from the variables $stout, $stderr. How can I do this and not without using $ssh = Net::SSH::Perl->new?

#!/usr/bin/perl
use strict;
use warnings;
use Net::SSH::Perl;
use FindBin qw($RealBin);
use File::Basename;
use lib "/nfs/site/proj/dpg/tools/lib/perl";
use Util;
use Getopt::Std;
use Net::SSH::Perl;
use Cwd;
use File::Copy;

my $host = 'someip.com.com';
my $pass = '';
my $user = '';
my $cmd  = 'pwd';

my($stdout,$stderr,$exit) = system('ssh someip.com cat /nfs/site/home/aa/test11.txt')        ;
if ($stdout) {
    print "Standard output is \n$stdout";
} elsif($stderr) {
    print "Standard error is \n$stderr";
}

Upvotes: 0

Views: 3396

Answers (3)

LeoNerd
LeoNerd

Reputation: 8542

I've always been a fan of IPC::Run:

use IPC::Run;

my $exitcode = run [ "ssh", "someip.com", "cat", ... ],
    undef, \my $stdout, \my $stderr;

At this point the STDOUT and STDERR results from the command will be stored in those two lexicals.

Though as a solution to the general issue of ssh'ing to a host and retrieving the contents of a file from within a Perl program, you might like IPC::PerlSSH:

use IPC::PerlSSH;

my $ips = IPC::PerlSSH->new( Host => "someip.com" );
$ips->use_library( "FS", qw( readfile ) );

my $content = $ips->call( "readfile", "/nfs/site/home/aa/test11.txt" );

The $ips object here will just hang around and allow for reuse to collect multiple files, execute other commands, and generally reuse the connection, rather than having to set up a new ssh connection every time.

Upvotes: 0

jchips12
jchips12

Reputation: 1227

I use IO::CaptureOutput, its simpler.

use strict;
use warnings;

use IO::CaptureOutput qw(capture_exec);

my $cmd = "ssh someip.com cat /nfs/site/home/aa/test11.txt";
my ($stdout, $stderr, $success, $exitcode) = capture_exec( $cmd );

You can also use list parameters in capture_exec which I think is safer.

Upvotes: 5

perreal
perreal

Reputation: 98108

open3 allows you to read/write all handles:

use FileHandle;
use IPC::Open3;
my $cmd = "ssh someip.com cat /nfs/site/home/aa/test11.txt";
open3(\*GPW, \*GPR, \*GPE, "$cmd") or die "$cmd";
    # print GPW "write to ssh";
close GPW;
while (<GPR>) { 
  # read stdout
}
while (<GPE>) { 
  # read stderr
}
close GPR; close GPE;

Upvotes: 1

Related Questions