# phpman > man > Net::SSH(3pm) ## NAME [Net::SSH](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH/markdown) - Perl extension for secure shell ## SYNOPSIS use [Net::SSH](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH/markdown) 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](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH%3A%3APerl/markdown) 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](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH/markdown) qw(sshopen2); use strict; my $user = "username"; my $host = "hostname"; my $cmd = "command"; sshopen2("$user\@$host", *READER, *WRITER, "$cmd") || die "ssh: $!"; while () { chomp(); print "$_\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](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH/markdown) 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)](https://www.chedong.com/phpMan.php/man/ssh-keygen/1/markdown) manpage. A #2: See [Net::SSH::Expect](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH%3A%3AExpect/markdown) instead. Q: My script is "leaking" ssh processes. A: See "How do I avoid zombies on a Unix system" in perlfaq8, [IPC::Open2](https://www.chedong.com/phpMan.php/perldoc/IPC%3A%3AOpen2/markdown), [IPC::Open3](https://www.chedong.com/phpMan.php/perldoc/IPC%3A%3AOpen3/markdown) 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 <> 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](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH%3A%3AExpect/markdown) or made into an ::Any style compatibility wrapper that uses whatver implementation is available ([Net::SSH2](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH2/markdown), [Net::SSH::Perl](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH%3A%3APerl/markdown) or shelling out like the module does now). Please email Ivan if you are interested in helping. John Harrison <> contributed an example for the documentation. Martin Langhoff <> contributed the ssh_cmd command, and Jeff Finucane <> updated it and took care of the 0.04 release. Anthony Awtrey <> contributed a fix for those still using OpenSSH v1. Thanks to terrence brannon <> 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](https://www.chedong.com/phpMan.php/perldoc/IPC%3A%3ASession/markdown) (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](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH%3A%3APerl/markdown) instead. For a wrapper version that allows you to use passwords, see [Net::SSH::Expect](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH%3A%3AExpect/markdown) instead. For another non-forking version that uses the libssh2 library, see [Net::SSH2](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ASSH2/markdown). For a way to execute remote Perl code over an ssh connection see [IPC::PerlSSH](https://www.chedong.com/phpMan.php/perldoc/IPC%3A%3APerlSSH/markdown). [ssh-keygen(1)](https://www.chedong.com/phpMan.php/man/ssh-keygen/1/markdown), [ssh(1)](https://www.chedong.com/phpMan.php/man/ssh/1/markdown), [IO::File](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3AFile/markdown), [IPC::Open2](https://www.chedong.com/phpMan.php/perldoc/IPC%3A%3AOpen2/markdown), [IPC::Open3](https://www.chedong.com/phpMan.php/perldoc/IPC%3A%3AOpen3/markdown)