A program using the command interpreter needs an initialization file. This file may be used in two ways. The first way is to let the interpreter read it at the beginning of the execution, the second way is to include it in the executable file (this is explained with more details in 14). The first way is better if one wants to be able to change some parameters of the program without having to recompile it. The second way is better if one wants to hide some aspects of the program or forbid any modification.
It is also possible to let the program write the initialization file somewhere in the user's home directory, making a copy of the one that is contained in the executable. In any subsequent execution of the program by the same user, only this new initialization file will be used. It can then be customized. This can be possible only if the second way of defining an initialization file is used.
This text file has several parts, which are described below. Any line in the initialization file beginning with the character ; is supposed to be a comment. Each part of the file (except for the last, which is a list of programs understood by the command interpreter ) begins with a line consisting of a keyword whose first character is a !, and sometimes ends with a point.
Some sections of the initialization file are optional, and some can occur several times. This can be useful to glue easily several applications of the command interpreter.
If the command interpreter detects an error in the initialization file it will print an error message to indicate the section where the error occured, and stop immediately.