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  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

index.html#Top Commands.html#Commands Gri: complete list of commands Gri: Command Syntax index.html#Top Gri: Command Syntax

9.1: Overview of Gri Commands

The Gri commands may be divided roughly into a few categories, as indicated in the following list.

  • Working with files: Commands are `open', `close', `skip', `read', and `rewind'.

  • Controlling parameters of the drawn material: 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.

  • Interacting with the user: The `query' command gets instructions from the user. The `show' command displays messages to user.

  • Controlling program flow: The `if' statement controls optional execution of commands (see If Statements). The `while' statement allows loops.

  • Moving around in directories: The `pwd', `cd' and `ls' commands do the usual unix things.

  • Using the 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).

  • Statistical operations: Some very limited capabilities exist; for example, `regress' does linear regression.

  • Mathematical operations: 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).

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