Gri: archiving old versions

Chapters: 1: Introduction 2: Simple example 3: Invocation 4: Finer Control 5: X-Y Plots 6: Contour Plots 7: Image Plots 8: Examples 9: Gri Commands 10: Programming 11: Environment 12: Emacs Mode 13: History 14: Installation 15: Gri Bugs 16: Test Suite 17: Gri in Press 18: Acknowledgments 19: License Indices: Concepts Commands Variables | ## 14.2: Archiving Old Versions Gri, like other complex programs, sometimes changes in such a way as to break old scripts. This is less so of changes since about 1998 or so, since the syntax became pretty firm about that time. Still, disk costs are so cheap that you would be well-advised to keep a backup version of Gri, whenever you update. This is pretty simple; you need to keep a copy of the executable and the library file, and you need to write a tiny shellscript that calls this particular executable with this particular library file. For example, you might do the following
    mkdir -m 755 -p           /usr/local/share/gri/2.12.23
    cp /usr/bin/gri           /usr/local/share/gri/2.12.23
    cp /usr/share/gri/gri.cmd /usr/local/share/gri/2.12.23
and then create a shellscript called ``/usr/local/bin/gri-2.12.23`' containing
    #!/usr/bin/sh
    /usr/local/share/gri/2.12.23/gri \
        -directory /usr/local/share/gri/2.12.23 \
        "$@"
to invoke this version of Gri. To be able to access this old version of gri from within the Emacs gri-mode, you would reset the Emacs variable ``gri*directory-tree`' like so in the file ``~/.emacs`' (see Step 2 in see Installing gri-mode.el)
    (setq gri*directory-tree
        '("/usr/local/share/gri/" "/usr/share/gri/"))