.. _setenv: ========================= Set environment variables ========================= The `export` commands below work in the bash shell. The syntax may be different in other shells. CLAW ---- To use the Fortran versions of Clawpack you will need to set the environment variable `CLAW` to point to the top level of clawpack tree (there is no need to perform this step if you will only use PyClaw). In the bash shell these can be set via:: export CLAW=/full/path/to/clawpack # to top level clawpack directory FC -- You also need to set `FC` to point to the desired Fortran compiler, e.g.:: export FC=gfortran # or other preferred Fortran compiler Consider putting the two commands above in a file that is executed every time you open a new shell or terminal window. On Linux machines with the bash shell this is generally the file `.bashrc` in your home directory. On a Mac it may be called `.bash_profile`. If your environment variable `CLAW` is properly set, the command :: ls $CLAW should list the top level directory, and report for example:: README.md riemann/ pyclaw/ amrclaw/ setup.py clawutil/ geoclaw/ visclaw/ classic/ PYTHONPATH ---------- If you used `pip` to install Clawpack then you should not set this environment variable. But if you installed without `pip`, e.g. following :ref:`installing_fortcodes`, then you need to set `PYTHONPATH` to include the directory `$CLAW`. If `PYTHONPATH` is already set, then you may want to insert `$CLAW` into the list of directories searched by Python via:: export PYTHONPATH=$CLAW:$PYTHONPATH See :ref:`python_path` for more information.