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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
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12.1: Overview of Gri Commands

The first word of a command hints at the meaning, but apart from that, here is a rough guide:
  • File manipulation Commands are `open', `close', `skip', `read', and `rewind'.
  • Control parameters Various `set' commands control values of parameters, like size of plot, linewidth, font, etc.
  • Drawing things Various `draw' commands let you draw data, axes, etc.
  • Interaction with user The `query' command gets instructions from the user. The `show' command displays messages to user.
  • Control program flow The `if' statement controls optional execution of commands see If Statements. The `while' statement allows loops.
  • Directory control The `pwd', `cd' and `ls' commands do the usual unix things.
  • Interaction with operating system The `system' command passes instructions to the operating system; the output may be saved into a synonym by using `\syn = system ...'. The `get env' command determines the value of any unix environment variables the system has defined. For more discussion see Operating System.
  • Statistics Some very limited capabilities exist; for example, `regress' does linear regression.
  • Mathematics Simple mathematical manipulation of column, grid, and image data is provided. Also, wherever Gri expects a number, it will accept a reverse-polish expression; for example, `set x size 10' could also be written `set x size {rpn 20 2 /}'. For details see Mathematics.
The data types in Gri are columns, grids, images, scalar variables and ``synonyms'' that is, strings see Synonyms, see Variables.
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