If the source command fails with a message like: 'source: not found' or you get many error messages indication that the command actually failed, you are very likely not using a command interpreter (shell) of a C-Shell flavour (e.g. csh or tcsh). Please replace the command `source my_script' by the following command `. my_script'
You really must type the `.' followed by a blank character before the
name of the script. Otherwise the setting of the environment variables inside the script will not be kept after the
script terminated.