Types Of Commands; How Cp/M Reads Command Lines - Commodore 128 System Manual

You can type the keyword and command tail in any combination
of upper-case and lower-case letters. CP/M 3.0 interprets all
letters in the command line as being upper case.
Generally, you must type a command line directly after the
system prompt. However, CP/M 3.0 does allow spaces between
the prompt and the command keyword.

Types of Commands

CP/M 3.0 recognizes two different types of commands: built-in
commands and transient utility commands. Built-in commands
execute programs that reside in memory as a part of the CP/M
operating system. Built-in commands can be executed
immediately. Transient utility commands are stored on disk as
program files. They must be loaded from disk to perform their
task. You can recognize transient utility program files when a
directory is displayed on the screen because their filenames are
followed by a period (full stop) and COM (.COM). Section 14
presents lists of the CP/M built-in and transient utility commands.
For transient utilities, CP/M 3.0 checks only the command
keyword. Many utilities require unique command tails. If you
include a command tail, CP/M 3.0 passes it to the utility without
checking it. A command tail cannot contain more than 128
characters.
How C P /M Reads Command Lines
Use the DIR command to demonstrate how CP/M reads
command lines. DIR, which is an abbreviation for directory, tells
CP/M to display a directory of disk files on your screen. Type the
DIR keyword after the system prompt, and press RETURN:
CP/M responds to this command by displaying the names of all
the files that are stored on whatever disk is in drive A. For
example, if the CP/M system disk is in the disk drive A, a list of
filenames like this appears on your screen:
A: PIP COM:ED COM:CCP COMrHELP COM:HELP HLP
A: DIR COM:CPM SYS
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