# Chapter 7. System Command Descriptions

This section contains descriptions for each of the command programs that are supplied with OS-9. These programs are usually called using the shell, but can be called from most other OS-9 family programs such as BASIC09, Interactive Debugger, Macro Text Editor, etc. Unless otherwise noted, these programs are designed to run as individual processes.

### Warning

Although many OS-9 commands may work on Level One or Level Two systems, there are differences. Take care not to mix command files from Level One systems on Level Two, or the reverse.

## Formal Syntax Notation

Each command description includes a syntax definition which describes how the command sentence can be constructed. These are symbolic descriptions that use the following notation:

[ ] | = Brackets indicate that the enclosed item(s) are optional.
{ } | = Braces indicate that the enclosed item(s) can be either omitted or repeated multiple times.
`path` | = Represents any legal pathlist.
`devname` | = Represents any legal device name.
`nodname` | = Represents any legal memory module name.
`procID` | = Represents a process number.
`opts` | = One or more options defined in the command description.
`arglist` | = a list of arguments (parameters).
`text` | = a character string terminated by end-of-line.

NOTE: The syntax of the commands given does not include the shell's built in options such as alternate memory size, I/O redirection, etc. This is because the shell will filter its options out of the command line before it is passed to the program being called.