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Getting started at LSCE (by JYP)

Welcome to LSCE!

You are probably reading this page because you are a new PhD or intern student, visitor, etc…
This page will help you survive your first steps at LSCE, at least survive using the computers (LSCE computers are your future best friends)…

Reading this page will save your life (and a lot of time)!

This page used to be for the newcomers in the CLIM and ESTIMR teams, but we can share information LOL

Miscellaneous information

A few useful links. Some have nothing to do with science and LSCE hardware/software resources!

Phone directory, and map of the building

Using existing information

  • Phone directory (intranet)
    • Dial 2 + NNNN (last 4 digits) to call somebody at LSCE (or CEA Saclay) from LSCE
    • Dial 0 + NNNNNNNNNNNNNNNNNNNN to call somebody outside LSCE from LSCE
    • Dial 18 to call FLS (CEA security & firemen)
  • 701 and 714 map (intranet)

Updating the directory/map information

It's very important that you update your phone/office information when you arrive at LSCE, so that other people can find you using the tools above!

Finding your phone number

Use the following sequence of keys on the Mitel phone in your office:

  1. Select MENU (use the downward arrow)
  2. Select PARAMETRES (use the downward arrow)
  3. Select GENERAL (use the downward arrow)
  4. Select MON NUMERO
    • This will display your 2 + NNNN phone number
    • You can be called from outside with 01 69 08 NN NN

Updating your entry in the directory

  1. Find your name in the phone directory
  2. Click on Modifier mes coordonnées (in blue on the right side)
  3. Click on Informations dans l'annuaire and update the different fields
  4. Click on Envoyez votre demande

The LSCE mailing lists

It is important to join the correct mailing lists, if you want to get all the information you need, on time.

The 'all' list

When your account is created, your email address should automatically be added to the the all list, that can be used to send mails to all the people working at LSCE. You will also get IPSL information through this list Everybody at LSCE People working at Orme People working in Gif

Mails sent to these lists will reach lots of people. Think well before sending a mail to these lists!

The teams mailing lists

Ask your team leader to add you to your team's mailing list. Example below: the CLIM and ESTIMR lists


  • You have to be identified on the server to access most lists's details. Enter you login and email password in the email address and pasword fields at the top right of any mailing list web page
  • You may want/need to join other mailing lists (project specific, sports, …). Check the list of lists to find about all the existing lists
  • It is possible to use mails to interact with the LSCE lists server, rather than the web interface

Using your own computer at LSCE?

You can't connect your personal laptop to the LSCE wired network (aka ethernet), it will not work!

The best you can do is use the Guest WiFi or eduroam network, if your office is close enough to one of the access points.

Warning! You can't connect directly to the obelix LSCE servers from the wifi network. You first have to connect to the gateway server, and then to obelix. More details in LSCE servers

Accessing the LSCE intranet

If you try to access the intranet from outside the LSCE network (including eduroam), your browser will open a login/password popup window.

Use your LSCE login (not your email address!) and password
e.g. use jdoe and not

Intranet web site:

There is a lot of information available on the LSCE intranet, but you can only access it from a computer connected to the LSCE network

Everything about the LSCE servers (and other software and hardware information):

Accessing the CEA Saclay intranet and other CEA web sites from a browser

LSCE is on the Paris-Saclay network (and not on the CEA network)

It is therefore not possible to access the CEA Saclay intranet by just clicking on from a computer on the LSCE wired network (or eduroam, or any network outside CEA)

Use the following steps:

  1. Start Chrome (or try another browser)
  2. Open the following link:
    • ignore the possible security/certificate errors
    • this link will work from the Paris Saclay network, and ANY other location (e.g. home) OUTSIDE of CEA
  3. Use your initials and badge number as the login (e.g. “James Bond” ⇒ “jb007007”) and the number supplied by the activIDentity keyring, followed by your 4 digits personal code, as your password
  4. Select the CEA web site you want from the “Aventail WorkPlace” portal
    • Espace Sigma: that's where you specify when you will be on holidays
    • Intranet Saclay: where you can get information about the CEA buses, CEA directory, security training registration and information, practical information, etc…
    • Intranet du voyageur: if you need to make a plane/train reservation
  5. Click on logout when you are done
    • … and close your browser Incognito window if you used one

Setting up your desktop computer

You should receive a desktop/laptop connected to the LSCE network when you arrive. Please take the time to read the instructions below, that may help make your life easier

Windows computer

Read the Windows 10 notes, especially the Configuring Windows 10 section

Getting administrator's rights

Make sure you know what you are doing and that you are not executing a virus asking you suspicious access rights!

If an application requests administrator's rights to install something or make changes to the computer, and you are sure it's not a virus, use the .\admin local account and the admin password you received when your computer was configured, or ask the system administrators.

Linux computer

There are different window managers available, each one with different settings: you should the Cinnamon window manager (xfce is a bit too basic, and Gnome is not very convenient for doing actual work, and uses too much CPU). You can select the window manager by clicking on the little cogwheel below the password field, on the login screen.

This is Linux, you are using it for work, you should be efficient, so you should be able to do most of your work by typing commands in a terminal. The true power is in the correct use of the command-line interfaces, rather than having to spend time finding where to click in the windows. You will find some Linux documentation below.

Using the root acount

Do not use the root account or privileges if you don't know exactly what you are doing!

Depending on what you need to do:

  • run a single command with the root access rights
    sudo command
  • become root in a terminal
    sudo su -
  • use the root password when a program asks for it. Be sure the programs have legitimate reasons to ask for the root password!


Sorry, you are (almost) on your own, but a Mac is soooo easy to use, right? 8-)

Some useful mac links:

Accessing the Windows cluster from a Linux computer

If you have a Linux computer, but need to use a Windows application, follow the instructions in the Windows servers page.

If you need to use a program that is missing on the Windows cluster, see the Help section.

Accessing the LSCE Linux servers

You have to use ssh to connect to the LSCE Linux servers, and use scp to copy files between servers

If you are really in a hurry, go directly to the Connecting to servers commonly used by LSCE users section, but it is important that you read the full ssh documentation page at least once!

Which Linux servers should you use?

Working directly on your desktop

Always remember that your local LSCE desktop/laptop can access remote disks on the LSCE servers.

There are lots of things you can do directly on your local computer (displaying pdf, images, using a text editor, …), rather than on the remote servers. For example, if a script running on the servers generates a pdf file, it is more efficient to open this pdf file using Acrobat/evince on your local computer, than by using evince on the server.

Available servers

  • The LSCE gateway:
    • Use ssh when you are outside the LSCE wired network, before accessing any other LSCE server:
      • By outside LSCE, we mean that your computer is:
        • connected to the LSCE WiFi network (instead of the wired network)
        • or physically outside LSCE
    • You can also use ssh1 when you are copying files to/from outside LSCE with scp or ssh-based tools
    • The ssh1 gateway can only be used for copying files or accessing the LSCE interactive servers!
      • You have to connect to an obelixNN interactive server before doing any real work
  • The LSCE interactive servers: obelixNN (obelix2 to obelix5)
    • Use ssh obelix to access the LSCE servers from inside LSCE.
      The load balancing system will send you to the obelixNN server that has currently the smallest load.
      • By inside LSCE, we mean that:
        • your computer is connected to the LSCE wired network
        • or you are using the LSCE VPN
        • or you have a terminal connected to the ssh1 gateway
    • Never forget that you are sharing these interactive servers with other users!
      • Do not use too much CPU and/or memory for a long time. Heavy computation should be done on the LSCE cluster
      • Learn how to use the top command to determine the current load of a server and the CPU/memory usage of your processes !
    • You can use one of the following commands if you want to know on which obelixNN you are
      • $ ssh obelix
        Last login: Mon Jun  3 08:49:53 2019 from somewhere
        $ echo $HOST
        $ hostname
    • In a python script, you can use the following to get some information
      • >>> import os
        >>> os.getlogin(), os.getenv('HOST')
        ('mylogin', 'obelix5')
  • The LSCE cluster (aka the batch system)
    Use this cluster for heavy duty programs, rather than killing the multi-users interactive servers
    • Heavy duty programs are programs that will prevent other users from working on the same server because these programs use a lot of CPU and/or memory for more than a few minutes. Ask your advisor, if you are not sure
  • The asterixNN servers
    Some wise LSCE elders may mention these servers, but they don't exist any more!

Which shell are you using?

It is important to know which shell you are using if you need to configure and tune your Linux account. The shell is basically the program that waits for you to type commands in a terminal and passes them to the computer

If you are not sure which shell is running in your terminals, you can use echo $SHELL to find out:

# Somewhere with tcsh
 > echo $SHELL

# Somewhere else with bash
 $ echo $SHELL

Determining the load of a Linux server

If the Linux server you are working on seems slow, or if you want to get an idea of the resources you are using, you should use the top command


top - 17:48:51 up 8 days, 23:43, 29 users,  load average: 1.22, 1.38, 1.98
Tasks: 324 total,   2 running, 320 sleeping,   2 stopped,   0 zombie
Cpu(s): 12.6%us,  0.0%sy,  0.0%ni, 87.4%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  32877756k total, 14706188k used, 18171568k free,    21372k buffers
Swap: 33554428k total,  1628972k used, 31925456k free, 14105940k cached

10193 john      20   0  302m 4336 2272 R 100.0  0.0   7033:08 emacs
16504 john      20   0  110m 2008 1228 S  0.7  0.0   0:00.13 tcsh
26344 jane      20   0 1635m  20m 3880 S  0.3  0.1   0:44.90 ipython
    1 root      20   0 21448 1108  892 S  0.0  0.0   0:01.61 init

The top lines give you some summary information about the system, but you should monitor the memory usage (VIRT and RES), CPU and TIME+ columns. By default, top will will put the processes using the more CPU at the top (as shown above). You can see above that the emacs text editor has clearly crashed, because it should not use 100% CPU for such a long time

  • The TIME+ information is in minutes (e.g. 5432:01 means 5432 minutes and 1 second, 25:15.20 means 25 minutes, 15 seconds and 20% of 1 second)
  • Memory usage:
    • %MEM (Kb): percentage of the total available physical memory used by a process. This is based on RES, the non-swapped physical memory used by a process
    • VIRT (Kb): total amount of virtual memory (i.e. memory temporarily swapped/saved to disk) used by a process. It includes all code, data and shared libraries plus pages that have been swapped out and pages that have been mapped but not used
    • The free command can display the memory usage of a server at a given time. available is an estimation of how much memory is available for starting new applications, without swapping
      •  % free -ht
                      total        used        free      shared  buff/cache   available
        Mem:            62G        1.5G         56G         11M        5.0G         60G
        Swap:           62G        1.7G         60G
        Total:         125G        3.3G        116G

If you type M, the processes will be sorted my memory usage, as shown below

16092 bob       20   0 8488m 8.1g 7912 R 99.6 25.9   1:41.38 idl
23256 john      20   0  232m  70m 2632 S  0.0  0.2   0:01.36 R
26344 jane      20   0 1635m  20m 3880 S  0.0  0.1   0:44.87 ipython
10619 bob       20   0  954m 9292 2664 S  0.0  0.0   0:40.67 gedit
 1362 nslcd     20   0  442m 6056 2208 S  0.0  0.0   2:13.98 nslcd
10193 john      20   0  302m 4336 2272 R 99.9  0.0   7024:13 emacs

Other useful keys:

q Quit
c Display the command line options of the running processes
u List only the processes of a specific user
M Sort by memory usage (%MEM columun)
P Sort by CPU usage (%CPU columun) (Default)

Using the kill command to terminate processes


kill proc_number

kill -9 -1


Which disks should you use?

  • It is very important to use the correct directories and make it easy for your advisor to find things after you have left
    • Put the source codes, scripts and papers you are writing on a backed up disk
      • The backed up disk at LSCE is home directory
        You should have a few Gb available on home
        Use the quota -s command to find out the exact amount
    • Put temporary files on a scratch disk (scratch01 at LSCE)
    • Do NOT put (big) data files on a backed up disk
  • Do not forget to clean your directories before you leave (ask your advisor what should be kept or cleaned)

Accessing remote disks

It is possible to directly access some disks on the LSCE servers from:

  • a Linux or Windows computer connected directly to the LSCE ethernet/wired network
  • or a remote computer using the LSCE VPN

For security reasons, only backed up disks and scratch01 can be accessed from Windows with dfs

e.g. if you have a /home/scratch01/your_lsce_login path on a Linux server, you can access it the following way from your desktop/laptop:

The home directory

  • Location: the location depends on the machine you are connected to in the current terminal
    • On the LSCE servers (obelixN): /home/users/your_lsce_login
      • Non LSCE servers:
        • TGCC: /ccc/cont003/home/dsm/your_tgcc_login
          You can find out the location of all your directories with ccc_home -a (use ccc_home -h to find out all the available options)
        • ciclad: /home/your_ciclad_login
    • On a local Linux desktop (lsceNNNN): /homel/your_lsce_login
    • The configuration files of your Linux account are stored in the home directory (use ls -a to see hidden files and directories). Ask your advisor if you should copy somebody else's configuration files
      • tcsh shell users: .cshrc and .login
      • bash shell users: .profile and .bashrc
    • You can go to your home directory by typing cd (no arguments),
      and to the home directory of somebody else with cd ~login_name
      • At LSCE, you can't read the content of somebody else's home directory by default
  • Backup of the home directory on the LSCE servers: YES! Every night
    • More details on the LSCE backup system page
    • Put the most important sources/scripts/data/papers in this directory
    • Do not use the home directory to store:
      • temporary files (use scratch01)
      • big (or many) data files (use scratch01 or a project specific disk)
    • Your home directory will be archived when your account is closed, so that you or your advisor can access it later, if required
  • Backup of the TGCC home directory: YES!
    • Use the following command to access the backup: cd ~/.snapshot
  • Quota: YES!
    There is a limit to what you can store in your home directory. If you reach this limit, you may experience some seemingly random errors (can't connect to the servers, the new files have a 0 size, …)
    The example below shows how to determine the quota on the LSCE disks: you can never go above the size displayed in the limit column, and you cannot stay more than 7 days above the limit displayed in the quota column! The grace column will display either None (you cannot write on the disk anymore, unless you get below the quota limit) or N days (you can use the disk, but you have N days to go below the quota limit)
     > quota -s
    Disk quotas for user johndoe (uid 6369):
         Filesystem  blocks   quota   limit   grace   files   quota   limit   grace
    prolix3:/users/   4658M   4883M   4981M           23503       0       0

The scratch directory

Do not put anything in the scratch directory that you can't recreate with a program, or copy/download from somewhere else!
  • Location: /home/scratch01/your_lsce_login
  • Backup: NO
    • Use this directory for temporary and big data files
    • The files older than 6 months (and possibly older than 1 month) will be automatically deleted if there is not enough free space. See the Scratch area section for more details on the retention policy
      • In other words, the files are guaranteed to stay 1 month and possibly longer
  • Quota: NO

Project specific directories

The data on these disks is probably not backed up… You are not protected against file deletion by mistake, or a disk crash (a major disk crash is not likely, but can happen)

You should store your source codes, scripts, notebooks, manuscripts, reports, figures, on a backed up directory, and only store on the project disks data downloaded from outside, or that you can regenerate with the backed up scripts

  • Location: /home/some_project_name/your_lsce_login
    • Ask your advisor if you should use a specific project directory and the technical details about it
    • Use this directory for storing the (big) data files that you can't store safely in the scratch directory, and should not store in the home directory
  • Backup: ask your advisor
  • Quota: ask your advisor

Determining the space used by directories

Your Linux environment may sometimes stop working correctly because you have exceeded the allowed quota on your disks (check your quotas with quota -s). You can use the following command to get the size of all the directories and files in the current directory, sorted by size: du -sh * | sort -rh

 >cd /home/scratch01/johndoe

 >du -sh * | sort -rh
47M     dashboard
15M     octcdf
3.2M    cmake

FIXME Add something about df

Which programs should you use?

Your advisor will let you know which (version of which) programs you should use. Some programs are available by default, and you have to use the module command to access other programs.

Which program am I using?

At any time, you can use the which command to determine where a program is located. The option to get the version information of a program may vary (launch the program without arguments, with -v or --v, …).

 > which ncdump

 > ncdump
ncdump [-c|-h] [-v ...] [[-b|-f] [c|f]] [-l len] [-n name] [-p n[,n]] [-k] [-x] [-s] [-t|-i] [-g ...] [-w] file
netcdf library version of Dec 10 2015 16:44:18 $

 > which python

 > python --version
Python 2.7.5

Using module to access optional programs

Most useful module options:

  • module list: list the currently loaded modules
  • module avail [mod_name]: list the available modules (or only the ones with a name starting with mod_name)
  • module load module_a … module_n: load modules (automatically including dependencies)
    • module load module_a: load default version of module_a
    • module load module_a/vvv: load vvv version of module_a
  • module purge: remove all modules

Detailed example:

 > which ncview
ncview: Command not found.

 > module list
No Modulefiles Currently Loaded.

 > module avail ncview

 > module load ncview netcdf/4

 > module list
Currently Loaded Modulefiles:
  1) ncview/2.1.7   2) netcdf/4
 > which ncview

 > which ncdump

Useful documentation for beginners


  • UNIX_doc_JYP.pdf: some basic Linux documentation. Make sure you read it!
    1. A list of the most useful commands
    2. A tutorial
  • Useful Linux commands for working with (potentially big) text files (houchesa4_updated.pdf)
  • Using ssh and scp

Text editors

A jupyter notebook is not a text editor!

You need a correct text editor to efficiently work with scripts and programs

xkcd & Real Programmers

There are lots of text editors available on Linux computers/servers (emacs, nano, vi, vim, gvim, gedit, …). You can use them:

  • In basic text terminals
    • If you only need to read a text file, use a pager like less (or more): less my_text_file.txt
      • SPACE goes down one page
      • b (back) goes back one page
      • /STRING looks for STRING in the text (then next, previous, quit)
      • q exits
    • nano is probably the easiest editor in text mode to use!
    • Useful if you are in a hurry, and/or working on a remote server with a bad network connection or have no local X server running
    • You should know the basic commands and shortcuts!
  • With a full Graphical User Interface (aka GUI) allowing you to use the mouse+menus/buttons/etc…
    • you will need to have a local X server running, if you want to use the text editor GUI on a remote server


Read the dedicated Using emacs page, and become a power user!

Gnu nano

Gnu nano is probably the easiest text editor in text mode to use!

You can easily view/edit a file by just typing nano my_text_file.txt in a terminal, and looking at the instructions displayed at the bottom of the screen (e.g. ^X Exit means that you can exit the editor by typing CTRL-X)

vi (vim, gvim)


Notepad++ is a nice and powerful text editor for Windows, but it is also very easy to install emacs on Windows

Super-short introduction to NetCDF

Some ways of working with NetCDF without programming

  • Displaying the content of a NetCDF file in a text format
    Check the ncdump options. People usually want to quickly check the metadata, and use other programs to work with the actual data
    • ncdump dump the full content to text
    • ncdump -h only display the metadata
  • You can use Panoply and ncview for quickly visualizing NetCDF files
  • Manipulating NetCDF files:

Using NetCDF with Python

Check the dedicated section of the Python page

Programming languages

Getting help (from the LSCE system administrators)

Send a mail to help-lsce

Describing your problem

When you need help from the administrators or other people, it will save a lot of time if you describe your problem as accurately as possible (do not just report XXXXX is not working as expected !)

You can copy-paste the error message(s). Finding the error log file(s) of the program/system (when available), or using the verbose mode of a program will make the problem resolution much easier and faster. The example below shows how to use the verbose mode of ssh

 >ssh -v obelix
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /home/users/johndoe/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
debug1: Connecting to obelix [] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/users/johndoe/.ssh/id_rsa type -1
debug1: Entering interactive session.
debug1: pledge: exec
debug1: client_input_global_request: rtype want_reply 0
debug1: Requesting X11 forwarding with authentication spoofing.
debug1: Sending environment.
debug1: Sending env LANG = en_US
Last login: Thu Mar  1 15:52:44 2018 from


Taking a screenshot

Sometimes, it may also help to send a picture of what is wrong!

On Linux, you should find a screenshot application in the tools available on the system. See the example below for people using the xfce windows manager Click to get a larger version

On Windows, you can use Snip & Sketch, or the Capture screen option of XnView Click to get a larger version

Getting help, when using the IPSL Mesocenter

Check the Contacts page

What next?

Ask you advisor, who has probably already told you everything that was listed above, so you did not really learn anything new by reading this page

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other/newppl/starting.txt · Last modified: 2024/04/24 12:37 by jypeter