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Using an MCS Linux PC

An introductory guide to using Linux on a Managed Cluster Service desktop.



This page is about using Linux on a PC in a Managed Cluster desktop. MCS Linux can also be used by remote login from any system. See also information on using DS-Files in MCS Linux and on printing using DS-Print.

In the instructions below, click means click the index finger button (left-hand button in the default mouse setup) unless otherwise specified.

Logging in

You will usually find that a PC in a MCS room is already switched on, and displaying a Windows information/start screen. If the screen is blank, move the mouse to wake the display. If the machine is switched off, switch it on and go to step 2, below.

  1. Hold down the Ctrl and Alt keys while pressing Delete. A warning message about use of the system is displayed; click on OK. At the Windows login screen click on the triangle at the right-hand side of the the red icon at the bottom right of the screen and, from the pull-down menu, select Restart.

  2. After some preliminary checks, the system will ask you to select the operating system to start; use the down arrow key to highlight MCS Linux and then press Enter ↵ to confirm your choice. If you wait too long to make your selection, the system will start the default operating system, which for most machines is Windows.

  3. A splash screen appears and the system continues to boot into Linux. If the system has to update itself this may take some time, and it may reboot.

  4. Once the machine has finished loading, it will display the system login screen (shown below). It will show a dialog box asking for your username. Enter your CRSid (e.g. spqr99) then press Enter ↵.

  5. The dialog box will then change, asking for your password. Enter your UIS Password, then press Enter ↵.

  6. Your desktop will then load.

MCS Linux login screen

Please remember to log out when you have finished. Failure to do so could result in another user reading, altering or deleting your files, or sending emails from your account.

The desktop

MCS Linux is based on Ubuntu and uses the Unity interface to the GNOME desktop environment. Once you have logged in, the login window shows the Message of the Day, the launcher on the left hand side of the screen and the top menu bar.

Hovering your mouse over an icon will show the application name or a short informative label.

log in screen

At the left of the top menu bar is the name of the currently active application. Moving the mouse to this will show the menu options for that application. At the far right are a set of information icons; clicking the mouse on each gives the menu for each icon. The icons are for communications, connection information, sound, date and time and, at the far right, the cogwheel icon menu includes access to system settings and log out controls.

Accessing applications through the menu system

Icons for commonly used applications (Dash HomeHome FolderFirefox and Google Chrome web browsers, the Thunderbird mail client, the LibreOffice suite, the GEdit plain-text editor, Terminal, and Settings) are in the launcher. To start one of these, single-click on the icon using the left mouse button.

To access the other applications in MCS Linux, click on the top icon in the launcher bar (Dash Home).

log in screen

The window that opens has several small icons at the bottom, that allow you to select different views.  The default icon, on the left, shows you applications and files you have recently used. The remainder, in order, gives access to the various applications available on the system; documents and folders you have accessed recently; and video, audio, and image files stored in your account.

Mouse and window operations

The main operations you may want are:

  • Mouse buttons: Clicking the right mouse button, for example on a window or on the background, gives a context-sensitive menu.

  • Windows: In the top corner of each window are three buttons that can be selected with the left mouse button (Window ops). The left button closes the window; the centre icon minimises the window (to the launcher); the right icon will maximise the window (to fill the screen). You can also:

    • Click and drag on the border of a window to resize it.

    • Click and drag on a window's title bar to move the window around the screen.

The command line interface

The fundamental application on an MCS Linux system is the command line interface, or shell, because every application that can be launched from the menu system can also be launched from the command line and there are many applications and utilities that only work at the command line. The shell also provides a syntax for combining commands and for running commands only under certain circumstances. If you want to do any automation for processing large numbers of files then you will need to understand the command line. If you are happy with the applications and commands provided by the menu system then you need not worry about it.

There are two ways to launch a window running a shell. You can either click on the Terminal icon in the launcher, or you can select Dash Home  Applications → Unix Shell, then select your preferred terminal type. Either way, you should have a window appear. If you have chosen Terminal using either method the terminal started will look something like this:

Terminal window

Once you see the prompt (sp999@scone:~$ in the image above) you can start typing commands.

Changing your password

See the instructions in IS 6: Changing/Choosing Passwords. If you have forgotten your password you will need to have it reset. See the FAQ on What should I do if I've forgotten my password or it doesn't work?.

MCS news

The Message of the Day is sourced from the UIS News service, and displayed at login-time.

Accessibility aids

The MCS systems are designed to be used by the widest possible audience and the operating systems include features that allow those with special needs to adjust their interface.

Standard facilities

The built-in accessibility facilities can be accessed from System Settings → Universal Access, and allows control over:

  • High-contrast rendering of screen elements;
  • Rendering of all text in larger type;
  • A screen-reader that describes desktop actions as they occur (toggle using Alt+Windows Key+S);
  • Visual alerting options;
  • Provision of an on-screen keyboard;
  • Sticky-, slow-, and bounce-key options;
  • Keyboard control of the mouse cursor.

Customizing the graphical interface

Customization of the colour-scheme used by the desktop is possible using the GNOME Color Chooser (gnome-color-chooser) application.  Though some skill is required to use this tool effectively, it may be useful for those users with visual impairments that find that both the default and high-contrast desktop themes are unsuitable for their needs.

Advanced customization of the visual presentation of the desktop is also available via the CompizConfig Settings Manager (ccsm).  As well as allowing you to load/unload a range of plugins, it also allows many plugin-specific settings and key-bindings to be customized.

Functions that can be enabled include:

  • Screen magnifier: causes an area around the mouse-cursor to be enlarged, which can be helpful for users with some types of visual impairment.  Enabling the screen magnifier is a three-stage process:

    1. First, you must load the Magnifier plugin by ticking the check-box next to it in the ccsm interface.
    2. Second, toggle on the screen magnifier function by typing Windows Key+M.  (As well as enabling the screen magnifier, this will unfortunately also load the "Music" dash; press Esc to close this again.)
    3. Finally, hold down Windows Key+SHIFT and scroll up or down on your mouse scroll-wheel to increase or decrease the amount of magnification applied.

    By default, only a relatively small window around the mouse cursor will be magnified; the size of this window can be adjusted in the Magnifier plugin's configuration options.

  • Negative: allows the colours of an individual window or the whole display to be negated.  This can be helpful for users with some types of visual impairment.

  • Dim Inactive: causes windows that are not in focus to be dimmed, so as to minimise unwanted distractions.  Once the plugin is loaded, this effect can be toggled by pressing Windows Key+P. This facility can be helpful for users with ADD and related conditions.

Further support

We publish general information and advice regarding accessibility issues of many kinds.  We also run the Assistive Technology office, which specialises in providing assistive technology advice, training, and support.

Applications available on MCS Linux

See the full software list for MCS Linux. Particular applications worth noting are:


The supported mail clients are ThunderbirdEvolution, and the command-line Alpine.

  • To use Alpine type alpine at the command line or, from Dash Home → Applications → Type, select Email & Messaging → Alpine. Alpine is preconfigured to connect to Hermes.

  • To use Thunderbird, type thunderbird at the command line or, from Dash Home → Applications → Type, select Email & Messaging → Thunderbird. Thunderbird will not be preconfigured, but has been pre-programmed with the details of the Hermes mail service; it should automatically fill in the right settings if you tell it your username is  If you require further assistance, have a look at the Thunderbird for Hermes help pages.

  • To use Evolution (email, contact management, appointment and task scheduling), type evolution at the command line or, from Dash Home → Applications → Type, select Email & Messaging → Evolution Mail & Calendar. Evolution is not preconfigured so if you wish to use it you will need to configure it; see Mail program settings for Hermes for help.

The Hermes webmail service is available using any browser.

Management of email (e.g. vacation messages, spam filtering) should be done through the webmail interface.

Web browsers

Firefox is the supported browser and can be started by single-clicking the icon in the panel (firefox icon).

Google Chrome is also provided — in three different versions.  Most users interested in using Chrome will want to use the stable version, however the beta and unstable versions of Chrome are also supplied, and may be useful for users wanting to experiment with browser features that are not yet finished.

Chromium is also available and can be accessed from Dash Home → Applications → Type, then select it from Web Browsing.

The Text-based browsers lynx and w3m are also available; to start these type the program name in a terminal window.

You will need to configure any unsupported browser that you wish to use.

Logging out

To log out click on the cogwheel item at the right of the menu bar at the top of the screen and choose Log Out. Doing this returns you to the login screen, from which you can login to Linux again or choose to reboot the system, e.g. into Windows. A machine left in this state for roughly 45 minutes will consider itself idle.  By default, idle MCS Linux workstations will reboot themselves into the default operating system on the system; on most machines, this will be Windows.

Known issues

Home directories exhibit some unusual behaviour

The network fileserver that hosts home-directories runs Windows.  As a consequence, it does not understand some Unix-specific conventions.  Specifically:

  • The file-server does not understand executable-bits.  To work around this issue, all files in your home-directory will be treated as having the executable-bit set. It is not possible to remove the executable bit from any file in your home-directory.

  • The Windows file permissions model does not map cleanly onto the Unix user/group/other model.  As a consequence, it is not currently possible for you to grant other users selective access to your personal files using the chmod (or an equivalent) command.

  • The file-server is case-insensitive. This is unusual for Linux and Unix systems, and means that it isn't possible to store two distinct files in the same directory with names that differ only in their case.  This has the consequence that you can give a filename in the wrong case when attempting to access a file, and that access will still work.

    For example, if you have saved a file called AAA.txt, and attempt to read it using the name aaa.txt, this will succeed. However, if you then try to save a new file in the same location called aaa.txt, or Aaa.txt, or aAa.txt, or similar, this will not create a new file, but will instead overwrite the original.

sudo commands will not work

The purpose of the sudo command is to run a specific program with administrative privileges.  Programs run with such privileges are not subject to the normal safety features that prevent modification, damage, or subversion of the operating system.  Therefore, the use of such commands is not allowed; any attempt to use a sudo command will result in a warning.

If you believe that an MCS Linux machine is broken, misconfigured, or lacking some essential functionality, please contact the service desk for support and advice.

Screen-locking is disabled

As a matter of policy, the ability to lock an MCS Linux desktop has been disabled, in order to avoid cases whereby a user leaves a machine locked for an extended period of time, preventing others from using it.

Changing your shell is not supported

All user accounts on MCS Linux are hard-coded to use the Bourne Again Shell, also known as bash.  It is unfortunately not possible to change your user shell.  If you try to change your shell using the chsh command, it will return the (somewhat misleading) error, "chsh: cannot lock /etc/passwd; try again later.".

Further information