$ROOTSYS doesn't appear

Hello! I’m a new ROOT user.When I attempt to use the command echo $ROOTSYS , it results in a blank output. Can someone help me to access or locate $ROOTSYS . The version of ROOT I’m currently using is 6.28/04. Thank you!

You need to source the thisroot script. Supposing you installed it (a binary, preferably) correctly (on Linux, I guess), follow step 4 in “Download a pre-compiled binary distribution” (and see the example just below):

You can get the information on where ROOT files are, using this:

root-config --prefix --exec-prefix --bindir --libdir --incdir --etcdir --tutdir

BTW. The “ROOTSYS” environment variable is usually/often used, but it is not mandatory.

Thank you it worked

Thank you it worked!