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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 `
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`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
...
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