Controlling prex From a Script

Enter commands to prex either from the prex command line or from a file containing prex commands.

When you start prex, it searches for a file named .prexrc first in $HOME/ and next in the directory from which you started prex. Commands are read from all files that are found. Therefore it is possible to have a .prexrc file in the current directory that overrides defaults that are set up by the .prexrc file in the home directory.

After reading any .prexrc files that are found, input is expected from the prex command line. To set up an experiment entirely using .prexrc files, the last statement in it can be quit resume, which quits prex but lets your program resume.

Also, when prex is running you can use the source filename command to specify a file from which prex reads commands. This file can have any name you like.

As with commands entered from the prex command line, all commands in the script should be in ASCII. The following rules apply:

• Terminate each command with the newline character.

• Continue a command onto the next line by ending the previous line with a backslash (\) character.

• Separate tokens by white space (one or more spaces or tabs).

• Start comments with a hash mark (#).

  While the command language is the same for prex commands entered from the command line and for commands from a script, commands that return output (such as list probes...) make little sense in a script because the output goes to stdout.