NAME¶

Net::SSH - Perl extension for secure shell

SYNOPSIS¶

  use Net::SSH qw(ssh ssh_cmd issh sshopen2 sshopen3);
  ssh('user@hostname', $command);
  issh('user@hostname', $command);
  ssh_cmd('user@hostname', $command);
  ssh_cmd( {
    user => 'user',
    host => 'host.name',
    command => 'command',
    args => [ '-arg1', '-arg2' ],
    stdin_string => "string\n",
  } );
  sshopen2('user@hostname', $reader, $writer, $command);
  sshopen3('user@hostname', $writer, $reader, $error, $command);

DESCRIPTION¶

Simple wrappers around ssh commands.

For an all-perl implementation that does not require the system ssh command, see Net::SSH::Perl instead.

SUBROUTINES¶

ssh [USER@]HOST, COMMAND [, ARGS ... ]

Calls ssh in batch mode.

issh [USER@]HOST, COMMAND [, ARGS ... ]

Prints the ssh command to be executed, waits for the user to confirm, and (optionally) executes the command.

ssh_cmd [USER@]HOST, COMMAND [, ARGS ... ]

ssh_cmd OPTIONS_HASHREF

Calls ssh in batch mode. Throws a fatal error if data occurs on the command's STDERR. Returns any data from the command's STDOUT.

If using the hashref-style of passing arguments, possible keys are:

  user (optional)
  host (required)
  command (required)
  args (optional, arrayref)
  stdin_string (optional) - written to the command's STDIN
    

sshopen2 [USER@]HOST, READER, WRITER, COMMAND [, ARGS ... ]

Connects the supplied filehandles to the ssh process (in batch mode).

sshopen3 HOST, WRITER, READER, ERROR, COMMAND [, ARGS ... ]

Connects the supplied filehandles to the ssh process (in batch mode).

EXAMPLE¶

  use Net::SSH qw(sshopen2);
  use strict;
  my $user = "username";
  my $host = "hostname";
  my $cmd = "command";
  sshopen2("$user\@$host", *READER, *WRITER, "$cmd") || die "ssh: $!";
  while (<READER>) {
      chomp();
      print "$_\n";
  }
  close(READER);
  close(WRITER);

FREQUENTLY ASKED QUESTIONS¶

Q: How do you supply a password to connect with ssh within a perl script using the Net::SSH module?

A: You don't (at least not with this module). Use RSA or DSA keys. See the
quick help in the next section and the ssh-keygen(1) manpage.

A #2: See Net::SSH::Expect instead.

Q: My script is "leaking" ssh processes.

A: See "How do I avoid zombies on a Unix system" in perlfaq8, IPC::Open2, IPC::Open3 and "waitpid" in perlfunc.

GENERATING AND USING SSH KEYS¶

1 Generate keys

Type:

   ssh-keygen -t rsa
    

And do not enter a passphrase unless you wanted to be prompted for one during file copying.

Here is what you will see:

   $ ssh-keygen -t rsa
   Generating public/private rsa key pair.
   Enter file in which to save the key (/home/User/.ssh/id_rsa):
   Enter passphrase (empty for no passphrase):
   Enter same passphrase again:
   Your identification has been saved in /home/User/.ssh/id_rsa.
   Your public key has been saved in /home/User/.ssh/id_rsa.pub.
   The key fingerprint is:
   5a:cd:2b:0a:cd:d9:15:85:26:79:40:0c:55:2a:f4:23 User@JEFF-CPU
    

2 Copy public to machines you want to upload to

"id_rsa.pub" is your public key. Copy it to "~/.ssh" on target machine.

Put a copy of the public key file on each machine you want to log into. Name the copy "authorized_keys" (some implementations name this file "authorized_keys2")

Then type:

     chmod 600 authorized_keys
    

Then make sure your home dir on the remote machine is not group or world writeable.

AUTHORS¶

Ivan Kohler <ivan-netssh_pod@420.am>

Assistance wanted - this module could really use a maintainer with enough time to at least review and apply more patches. Or the module should just be deprecated in favor of Net::SSH::Expect or made into an ::Any style compatibility wrapper that uses whatver implementation is available (Net::SSH2, Net::SSH::Perl or shelling out like the module does now). Please email Ivan if you are interested in helping.

John Harrison <japh@in-ta.net> contributed an example for the documentation.

Martin Langhoff <martin@cwa.co.nz> contributed the ssh_cmd command, and Jeff Finucane <jeff@cmh.net> updated it and took care of the 0.04 release.

Anthony Awtrey <tony@awtrey.com> contributed a fix for those still using OpenSSH v1.

Thanks to terrence brannon <tbone@directsynergy.com> for the documentation in the GENERATING AND USING SSH KEYS section.

COPYRIGHT¶

Copyright (c) 2004 Ivan Kohler. Copyright (c) 2007-2008 Freeside Internet Services, Inc. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

BUGS¶

Not OO.

Look at IPC::Session (also fsh, well now the native SSH "master mode" stuff)

SEE ALSO¶

For a perl implementation that does not require the system ssh command, see Net::SSH::Perl instead.

For a wrapper version that allows you to use passwords, see Net::SSH::Expect instead.

For another non-forking version that uses the libssh2 library, see Net::SSH2.

For a way to execute remote Perl code over an ssh connection see IPC::PerlSSH.

ssh-keygen(1), ssh(1), IO::File, IPC::Open2, IPC::Open3