I am writing a little install script for some software. All it does is unpack a target tar, and then i want to permanently set some environment variables - principally the location of the unpacked libs and updating $PATH. Do I need to programmatically edit the .bashrc file, adding the appropriate entries to the end for example, or is there another way? What's standard practice?

Edit: The package includes a number of run scripts (20+) that all use these named environment variables, so I need to set them somehow (the variable names have been chosen such that a collision is extremely unlikely)