Running ROOT on Lxplus Server of CERN

Mac OsX terminal window has powerful features than any other operating systems but if you are working on a remote server you need to know a little more about it.

If you are using MacOSX and if you are connecting lxplus@cern using regular command ssh, the first thing you will observe is that your system cannot open X11 window which is needed by ROOT. To overcome this problem, you should connect using either

ssh -X username@lxplus.cern.ch
or
ssh -Y username@lxplus.cern.ch

X option, provides you a ssh connection forwarding X11. And Y option, provides a ssh connection Forwarding trusted X11.

After you logged in using your user name and password, you have 2 options to run ROOT.

1 -) Entering ROOT variables below:

export ROOTSYS=/afs/cern.ch/sw/lcg/app/releases/ROOT/5.28.00/i686-slc5-gcc43-opt/root
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROOTSYS/lib
export PATH=$PATH:$ROOTSYS/bin

2-) Or just source Athena Framework and setup root from Athena: (Note that Athena consists much more than ROOT)

export AtlasSetup=/afs/cern.ch/atlas/software/releases/16.6.0/AtlasSetup
alias asetup='source $AtlasSetup/scripts/asetup.sh'
asetup 16.6.0


–Recently this procedure has been changed and became eaiser. Please google for sourcing Athena framework–

Then just write “root” and start your analysis.