For the impatient

We have worked hard to insure that the CRAB install at the Nebraska T3 is as easy as possible.  For the impatient, one can simply source the following script:

source /opt/ui.sh

then use crab as normal.  The first time you run this in your user account, it will complain about BOSS not being setup.  Run this script afterwards:

$CRABDIR/configureBoss

If there are any CSH users out there, please ask an admin to come up with a CSH equivalent.

A few more details

CRAB documentation most certainly does not belong at the T3 site.  The script referenced above will configure the necessary environment so you can follow along with other, more authoritative tutorials.

That said, I document a sample CRAB session below.  First, setup the UI (User Interface) environment:

source /opt/ui.sh

If prompted, run this script afterward:

$CRABDIR/configureBoss

The rest will follow the FNAL tutorial, adopted for the Nebraska T3.  We will be running an analysis on this dataset:

/RelVal131Higgs-ZZ-4Mu/CMSSW_1_3_1-1176118250/GEN-SIM-DIGI-RECO

Install the CMSSW project directory:

mkdir Tutorial
cd Tutorial
scramv1 p CMSSW CMSSW_1_3_1
cd CMSSW_1_3_1/src
eval `scramv1 runtime -csh`

Then, download the sample code and build it:

wget  http://cmsdoc.cern.ch/cms/ccs/wm/www/Crab/Demo.tgz 
tar zxvf Demo.tgz
scramv1 b

There should be no errors up to this point; if there are, please contact an admin.  Next, change directory to:

cd  Demo/MyTrackAnalyzer/test/

Create a file called crab.cfg and place the following contents in it:

[CRAB]
jobtype                = cmssw
scheduler              = glitecoll

[CMSSW]
datasetpath            = /RelVal152Z-MM/CMSSW_1_5_2-RelVal-1184071556/GEN-SIM-DIGI-RECO
pset                   = higgs.cfg
total_number_of_events = 100
number_of_jobs         = 10
output_file            = histograms.root

[USER]
return_data            = 1
use_central_bossDB     = 0
use_boss_rt            = 0

[EDG]
rb                     = CERN 
proxy_server           = myproxy.cern.ch 
virtual_organization   = cms
retry_count            = 0
lcg_catalog_type       = lfc
lfc_host               = lfc-cms-test.cern.ch
lfc_home               = /grid/cms

Create the jobs with the following command:

crab -create

Followed by the submit command:

crab -submit

This will submit your jobs to the grid.  It may take awhile for them to run; you can monitor their progress with the following command:

crab -status

Finally, when the jobs are done, you can retrieve output with the following:

crab -getoutput

(Again, this is not CRAB documentation.  If you would like longer explanations of the above command, check the CRAB homepage.)
This will copy the root files to your local disk.  Beware: the grid can only transport up to 10MB in this manner.  If you want more than 10MB of output per job, then you must use one of CRAB's separate stageout techniques.  The following needs to be edited/changed to get stageout to UNL's dCache working:

[USER]                                                                                                                              
return_data = 0
                                                                                                                                                  
copy_data = 1
storage_element = srm.unl.edu
storage_path = /srm/managerv1?SFN=/pnfs/unl.edu/data4/cms/store/users/u/username/subdir

(Obviously, you need to change the /u/username portion).  At some point, stageout directly to the T3 node will be explained on this page.