Gri Commands
1: Introduction 2: Simple example 3: Fancy example 4: Running Gri 5: Programming Gri 6: General Issues 7: X-Y Plots 8: Contour Plots 9: Image Plots 10: Examples 11: Handling Data 12: Gri Commands 13: Gri Extras 14: Evolution of Gri 15: Installing Gri 16: Gri Bugs 17: System Tools 18: Acknowledgments 19: License 20: Newsgroup 21: Concept Index |
12.14: The `
|
`get env \result \environment_variable' |
getenv
'). This command can be useful in making gri programs
resistant to changes in data-file locations. Suppose, for example,
there is a file called `data', normally in a local directory called
`Bravo
'. The line `open Bravo/data
' will fail if the Bravo
directory is moved. But if the name of the datafile is stored in an
unix environment variable, `DIR_BRAVO
' say, then the gri program will
work no matter where the Bravo data are moved, so long as an appropriate
environment variable is modified when the data are moved. Example:
get env \dir DIR_BRAVO if {rpn "\dir" "" ==} show "Cannot determine location of the Bravo data," show "which should be stored in the environment" show "variable DIR_BRAVO. You should" show "do something like" show "export DIR_BRAVO='/data/Bravo/'" show "in your ~/.environment file" quit quit end if open \dir/data ... |