Command Line
============

This chapter gives an overview of how to manage a ThinLinc cluster using
the command line. Detailed descriptions of available commands can be
found in :ref:`commands`.

.. note::

   It is recommended to configure :command:`sudo` so that these commands
   can be run without having to specify an absolute path. See
   :ref:`install_sudo_configuration` for details.

Managing Sessions
-----------------

Users' sessions can be examined and controlled using :program:`tlctl
session`. With this tool, it is possible to list sessions currently
running on the cluster:

.. code:: console

   $ sudo tlctl session list
   USER   DISPLAY  AGENT               STATUS     AGE
   ========================================================
   alice  12       agent1.example.com  connected  11 day(s)
   bob    32       agent2.example.com  connected  5 hour(s)

   Listed 2 session(s).

If only some sessions are interesting, then it is possible to list just
those:

.. code:: console

   $ sudo tlctl session list --agent agent2.example.com
   USER  DISPLAY  AGENT               STATUS     AGE
   =======================================================
   bob   32       agent2.example.com  connected  5 hour(s)

   Listed 1 session(s).

It may happen that something has gone wrong with a user's session and
needs to be restarted. The :program:`tlctl session` command can then be
used to terminate that session:

.. code:: console

   $ sudo tlctl session terminate --user bob
   Refreshing session information...

   Terminating:
   USER  DISPLAY  AGENT
   =================================
   bob   32       agent2.example.com

   Summary:
     Terminate 1 session(s)

   Is this ok? [y/N]: y

Notifying Users
---------------

Sometimes it may be necessary to inform users of important events, e.g.
that a server needs to be restarted. Historically, the :command:`wall`
command was used for this, but it is mostly ignored by desktop
environments and users may not have a terminal open.

ThinLinc includes the tool :program:`tl-notify` that instead uses the
notification mechanism built into most desktop environments. With this
tool, it is easy to send a message to users:

.. code:: console

   $ sudo tl-notify The system will be restarted in one hour

Note that this command only notifies the users on the agent where the
command is run. It is therefore recommended to also use
:program:`tl-ssh-all`:

.. code:: console

   $ sudo tl-ssh-all tl-notify The system will be restarted in one hour

.. _cli_load:

Cluster Load
------------

The current status of ThinLinc's load monitoring can be examined using
:program:`tlctl load`. The command :program:`tlctl load list` can be
used to get a brief overview of the entire cluster:

.. code:: console

   $ sudo tlctl load list
   AGENT               USERS  MEM  CPU  RATING
   ===========================================
   agent1.example.com     11  14%   0%   10.85
   agent2.example.com     10  10%   0%   29.88

More details can be fetched about a specific agent using :program:`tlctl
load show`:

.. code:: console

   $ sudo tlctl load show agent.example.com
   DETAILS FOR AGENT "agent1.example.com"
   --------------------------------------
          Number of users: 11
   Memory (used RAM+Swap): 14%
         RAM (used/total): 0.5/1.8 GiB
        Swap (used/total): 0.0/1.6 GiB
             Load (1 min): 0.0
           Number of CPUs: 2
                      CPU: 0%
                 Bogomips: 11999.98
                   Rating: 10.85
           Penalty points: 0
             Last updated: 24 s ago