Setup

To use the software which is installed, the machine needs to know where it is. For example, the executables that you can run in a shell without specifying the full path are the ones in the PATH environmental variable. Run

echo $PATH

to see it. Typically, executables require libraries to function correctly. To include the necessary libraries, you can manipulate the LD_LIBRARY_PATH variable. Similarly, for Python modules, you can configure the PYTHONPATH variable.

Warning

There are more efficient methods to achieve these objectives. For instance, on your personal laptop, it's generally advisable to avoid direct manipulation of these variables and instead rely on your package manager.

There are standardized approaches for setting up software on machines that mount CVMFS, such as Proof and Lxplus.

export ATLAS_LOCAL_ROOT_BASE=/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase
source ${ATLAS_LOCAL_ROOT_BASE}/user/atlasLocalSetup.sh

These commands are very popular so it is common to add to your .bashrc (or similar files) the following (to use them you need to restart a new shell):

export ATLAS_LOCAL_ROOT_BASE=/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase
alias setupATLAS='source ${ATLAS_LOCAL_ROOT_BASE}/user/atlasLocalSetup.sh'

So that you can just run

setupATLAS

Tip

It is better to don't mix setups, so if you want to setup a new setup, restart a new clean shell

Try to setup ROOT:

lsetup ROOT

Warning

Presently the command will complain since you need to specify a particular version, just follow the instructions in the message

Now you have ROOT, look where it is from:

which root

You can start it:

root

Use Ctrl+D to exit.

Have a look at the tutorial about the atlas setup.