1. Basic aliensh
S. Bagnasco, INFN Torino
CNAF Nov 27-28, 2007

2. Preparing the certificates
Certificates should be stored
under $HOME/.globus
Globus enforces privacy on your private key!
(chmod 400)

3. Changes in environment
. /tmp/gclien_env_…

4. Getting a GRID proxy Authentication command
(default is the local username)
Happens every 24 hours
Put certificate password

5. Getting an AliEn token

6. Authentication problems I
Globus related:
Permissions on $HOME/.globus/userkey.pem are not private to the user
chmod 400 userkey.pem
Your certificate authority is exotic and not known to the server.
Your certificate has expired.
Clock skew:
Your local computer time is in the future with respect to the server's time.
Your local computer time is more in the past than the certificate life time.

7. Authentication problems II
alien-token-init related:
You have not gone through all 5 steps of the AliEn user registration.
You have not given the AliEn user name as an argument to the token-init command and your local user name is not identical to the AliEn user name.
The script wants to bootstrap the installation but you don’t have write permissions on the installation path
Avoid bootstrapping by setting the GSHELL_ROOT environment variable.
API servers are not working…

8. Try it out! Upload your certificates to your machines:
Store them under e.g: /afs/cern.ch/user/t/trn2301/.globus/
Check that the key file is read only.
Get a valid alien token.
If asked if you want to compile the gapi and xrootd libs answer YES (everything is already precompiled)

9. Accessing the shell Message of the day.
Standard bash shell with grid comands
Main bash features are available.
Not all shell helper programs are available.
Some local commands (like ls, cat etc) are overwritten
with the corresponding GRID commands.
File/path tab completion in the virtual GRID directory.
Message of the day.

10. Tab completion working!!!
Shell Basic commands I
Tab completion working!!!

11. Shell Basic commands II

12. Shell Basic commands III

13. whereis command

14. Viewing files I

15. viewing files II

16. Editing files Define your preferred editor via the variable EDITOR:
'emacs'
'emacs -nw'
'xemacs'
'xemacs -nw'
'pico'
'vi' (DEFAULT)
'vim'
The file is temporary in /tmp on your local disk and then is
uploaded once you exit the editor!

17. Clean up old versions

18. Copying out files GOLDEN RULE
If you want to access your local directory structure while you
are in the shell you should start by having the prefix “file:”
e.g: cp file:/home/pchrist/gshell.sh gshell.sh

19. File catalogue structure
The path name will be:
for ‘real’ data: /data/<Year>/<AcceleratorPeriod>/<RunNumber>/
for simulated data: /sim/<Year>/<ProductionType>/<RunNumber>/
Subdirectories will be called:
Raw/
cond/
reco/<PassX>/ESD/
reco/<PassX>/AOD/ …
File names will look like this: <xxxx>.AliESD.root
For further information see:

20. Querying the File Catalogue
aliensh:[alice] [1] find -x pp
/alice/cern.ch/user/p/pchrist/Tutorial/PDC06/*
*Merged*tag.root > pp.xml
Redirect the output to
the xml collection.

21. Querying the File catalogue
aliensh:[alice] [1] find -x pp
/alice/data/2008/LHC08a/*/reco/Pass3/*
*Merged*tag.root
Run:collision_system=”pp” and
Run:stop<" :20:33" and
Run:start>" " > pp.xml

22. Try it out I Access the alien shell and try some simple commands:
Check your user name by typing ‘whoami’.
List the contents of your home directory.
Print the working directory.
Create the following directory structure in your AliEn space:
$HOME/bin (if it is not there)
$HOME/GridSchool
Get the information of the file with ‘whereis’:
/alice/cern.ch/user/s/sbagnasc/GridSchool/GridSchoolNov2007.tgz
Check $HOME

23. Try it out II Try the -v option!
Copy the AliEn file /alice/cern.ch/user/s/sbagnasc/GridSchool/GridTutorial-November2007.tgz to your local $HOME/GridSchool
Exit the shell and unpack the file locally by typing: tar xvzf GridSchoolNov2007.tgz
Enter again the shell and register:
The .csh files in your AliEn $HOME/bin
The .jdl files in your AliEn $HOME/GridSchool
Try the -v option!

24. Try it out iII Play with the ‘find’ command:
Access the shell again and query the f.c. and get all the tag files (*.tag.root) under: /alice/sim/2007/LHC07c/pp_minbias/8268/*
Get the output on your terminal (find /alice/…)
Get the output on your terminal in a xml format (find -x tag /alice/…)
Redirect the results to the tag.xml collection: the output will not be stored in your AliEn working directory but rather in your local working directory.
Repeat the previous exercise limiting the number of output files to 5 (find -l 5 ...).

25. Tomorrow Whatever is left over from today…
Write a JDL to generate some file
Submit the job and check its progress
Check the job’s output
Write a JDL to look at the output
Submit it to run wherever the file is
Get the result
If there is some time left, do the same actually generating MC events and reconstructing them, or even analyzing some PDC data…