====== The Lofar Login Environment (LLE) ======

This page describes the standard login environment for new users on the LOFAR cluster nodes like [[:cep3:start|CEP3]]. Existing accounts can be easily modified; see below for a manual to do this.

===== General =====

The Lofar Login Environment sets a few things for your account, and allows you to easily initialise often used packages and tools at login time. To this purpose we provide a few simple standardized login-scripts.

===== Use (t)csh or bash! =====

To be able to use the LLE environment you must either use a ''(t)csh'' or ''bash'' login shell. We do not support scripts for any other shells.
===== What to do when you get an account =====

The CEP3 user creation system has been setup such that new accounts will have all needed files and links in ''$HOME'' in place already. So you do not have to chnage anything to work with the LLE.
===== How to transform existing accounts? =====

To use the LLE in an existing account and ''$HOME'' dir, rename your existing ''.cshrc'', or ''.profile'' and ''.bashrc'', in your ''$HOME'' and follow the instructions given above.
===== The LLE scripts =====

Some of the details are presented here.

==== Login scripts ====

In directory ''/opt/cep/login'' are a number of default login scripts. The scripts ending with ''.bash'' are for the ''bash'' shell, the others for the ''(t)csh'' shell:

   * ''cshrc''  → login settings for (t)csh environments.
  * ''bashrc''  → login settings for non-interactive logins.
  * ''profile''  → login settings for interactive logins.
  * ''login''  → Displays welcome message; no settings.
  * ''setpackages''  → script to define packages to initialize at login-time.

Users should **NEVER**  modify these default scripts. In their ''$HOME''  these should be symlinks to the versions in ''/opt/cep/login''. Personalization of your login is possible through other scripts like ''.myalias''  and ''.mysetenv''  (see below).

If you like to read more on the files that play a role in the bash login, [[https://stackoverflow.com/questions/415403/whats-the-difference-between-bashrc-bash-profile-and-environment|here is a nice link]].

==== Personal command aliasses: .myalias ====

Personal command aliases can be added to a file ''$HOME/.myalias''. When this file exists, the ''.cshrc''  or ''.bashrc''  script will read this file.

==== Personal environment settings: .mysetenv ====

Personal extensions to ''$PATH'', personal environment variables, personal prompt setting, or overloaded existing environment variables should be done in a file ''$HOME/.mysetenv''. If this file exists, the cshrc or bashrc script will read this file.

===== Package initialisation =====

Many packages are available from the distribution of the Operating System. Several packages are added lateron, see [[:cep3:usersoftware|this page for CEP3 packages]]. To activate these, environment variables like ''PATH'', ''LD_LIBRARY_PATH'', ''PYTHONPATH''  must be set correctly. To help you, we have installed the environment module software (see [[:cep3:usersoftware#using_packages_with_environment_modules|this section in the CEP3 user documentation]]).

==== .mypackages ====

To initialize the use of installed packages at login time you must create a file ''$HOME/.mypackages''. If this file exists, it is used by the LLE script ''setpackages''.

The file ''$HOME/.mypackages''  can look like this example:
<code>

casa
lofim

</code>

Provide only one package name per line. For packages that are build daily and that have a version available for all days of the week (LUS, LofIm), you can also specify a day of week in the ''.mypackages''  file:

<code>
lofim Tue

</code>

==== How to add a personal package ====

Apart from the systemwide module initialization files provided in directory ''$APS_LOCAL/modulefiles'', users can add their personal modulefiles in their ''$HOME/modulefiles''  and have these run at login time. To add a new, personal, modulefile, act as follows:

  * Install the package
  * Create a ''$HOME/modulefiles/<package>/<modulefile>''  environment module script (e.g., adding the installation directory to your ''$PATH''). See [[http://modules.sourceforge.net/man/modulefile.html|this manual for writing modulefiles yourself]].
  * Add <package> to the list of packages in file ''$HOME/.mypackages''

===== Starting X environment =====

To start up an X environment you have to make sure that

  * The files ''$HOME/.xinitrc''  and ''$HOME/.xsession''  are removed

Determine the colordepth that you need (8, 16, 24 bit display) and type:
<code>

  startx -- :1 -depth <colordepth>

</code>

This should start your X environment at the proper colordepth. This will create an additional X Server next to the one you are already running. You can access this with Alt-F8 or Cntl-Alt-F8. The F7 variant will give you back your normal X.

Due to the large latency and largte bandwidth required for X-traffic, it is advisable to connect to the CEP systems with the ''NX''-client on your system. See [[:public:freenx-windows-client|this page for more info]].

===== Help! =====

If you need help, or have questions, or want to give any other comments, contact Arno Schoenmakers or Jasmin Klipic.

New module-files can be added at any time if you have a new package that should be available systemwide. Contact Arno Schoenmakers or Jasmin Klipic in this case.