There are two ways to program with the command interpreter. The first is to write a sequence of commands in a command file in the command directory (cf. 3.4). For instance, if the name of this file is name_of_file, the command
< name_of_file
will launch the reading of the file and the execution of all the commands in it.
The second way is to write programs (i.e. sequences of commands or calls to programs), load them and execute them as commands.
Both command files and programs accept parameters and can call programs or read command files.
In a prior version of the command interpreter the possibility to load and execute programs was not implemented. Programs are easier to use and run faster than command files. Moreover everything done with command files can also be done with programs. Nevertheless the possibility to use command files has been kept in this version of the command interpreter.
It is possible to have several programs running simultaneously (i.e. threads). This is explained in chapter 10.