---
layout: page
category-page: intermediate
category-title: Intermediate commands
tags: remote connection host server file
author: Announ Marwan
title: ssh
---

The <code>ssh</code> command is used to operate with a remote machine using
the <i>ssh</i> protocol. It's commonly used for logging into a remote
machine and execute commands from a terminal interface.


<h3>Log into a server</h3>

To log in a remote server you need an user account which is
usually created by the server admin and a password.

<pre>
localhost:[~]&gt; ssh username@remote-server
remote-server:[~]&gt;
</pre>

Once you're logged in, the local machine shell will be
<i>replaced</i> by the remote server's one.<br>

<h3>Log out of a server</h3>

<ul>
    <li>Press <code>⌘ + D</code></li>
    <li>Run the command <code>logout</code></li>
    <li>Run the command <code>exit</code></li>
</ul>

<h3>Run a command on a remote machine</h3>

<pre>
localhost:[~]:&gt; ssh user@remote-host "ls test"
    online-backup.dat
    online-storage
    unix-dedicated-server.txt
</pre>


<h3>Debug the client</h3>

Debugging the ssh client can be useful to resolve connection errors.

<pre>
localhost:[~]:&gt; ssh -v user@remote-host
    OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
    debug1: Reading configuration data /etc/ssh/ssh_config
    debug1: Applying options for *
    debug1: Connecting to remote-host [172.22.200.140] port 22.
    debug1: Connection established.
    debug1: identity file /home/user/.ssh/identity type -1
    debug1: identity file /home/user/.ssh/id_rsa type -1
    debug1: identity file /home/user/.ssh/id_dsa type 2
    debug1: loaded 3 keys
    ...
</pre>