VP fix and MS-DOS Primer
USING DOS COMMANDS
Once you have entered the VP fix Environment, you can run both DOS and UNIX commands and programs. This section discusses how to use DOS commands. In this section you will learn:
• What a DOS command is.
• DOS command syntax.
• What options and arguments are.
• How to issue a DOS command.
• How to stop a DOS command.
What Is a Command?
The words command and program are nearly synonymous. In sim-ple terms, the user types a command, followed by IRETURNl, and the operating system executes the program that performs the user's
"command."
Commands are typed at the system prompt. When a command is entered, it is called a command line. It can have three parts: the command itself, its options (also referred to as switches and flags), and its arguments. The command name is the name of the program that performs the desired action. An option is a special kind of argument that is specific to a particular command. It changes the behavior of the command in some way. In the DOS operating sys-tem, an argument usually consists of a file, directory, user name, or drive name. (The UNIX operating system does not use drive names.) An argument gives the system information that is required to process a specific command or to change the standard behavior of a command.
Each command line is terminated by using
1
RETURNI.
The IRETURN! key is labelled IENTER! on some systems and is fre-quently referred to as IENTER! in DOS software documentation.When the IRETURNl is received, the command is sent to the operat-ing system for execution.
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Command Syntax
The UNIX operating system is case sensitive, which means that it distinguishes between upper- and lowercase letters. The DOS sys-tem is case insensitive, that is, it does not distinguish between upper- and lowercase letters. Throughout this document, commands are shown in lowercase letters; however, you can use any combina-tion of uppercase and lowercase letters when typing commands to the DOS operating system. It converts everything you type to uppercase letters.
",. When using a UNIX command, you may not use either upper-or lowercase characters; you must type the command in the correct case.
DOS options typically begin with a forward slash (I). Each com-mand, option, or argument consists of one word, which is interpreted as a group, or string, of characters surrounded by spaces.
If you make an error when typing a command, use
I
BACKSPACEI
to correct the error. You may use the left and right cursor positioning keys (such as EJ), but you may not use the up and down cursor positioning keys (such as 1]).Always type the command name first, followed by a space. Next type the desired option or options, each followed by a space, then any arguments, separated by spaces. (Y ou can also use the semi-colon (;), the equal sign (=), or ITABI between DOS commands and their options. In this manual, commands and options are shown separated by a space.)
This primer presents commands in the following format:
VPjix and MS-DOS Primer - Release 1.1.0
COMMAND NAME FORMAT
DESCRIPTION
OPTIONS
ARGUMENTS
command name
command [option( s) 1 argument(s) A brief description of what the command does.
A list of the most useful options and a brief description of each.
Mandatory or optional arguments.
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If an argument is not required, it is shown in square brackets [
1.
Options are always "optional," so they are always shown in square brackets. Only the most common options and arguments are dis-cussed in this primer. Some commands may also include step-by-step instructions. For a complete list of the available options and arguments, refer to the MS-DOS Reference Guide.
Command Names
Command names are short or abbreviated words that describe the programs they invoke. They are deliberately kept short to save time and reduce typing errors. On DOS systems, you can abbreviate some command names to two or three letters. For example, you can either type rename or ren when using the rename command.
(Note that this is not true on UNIX systems.) In the discussion of each command, there may be information on acceptable abbrevia-tions (or substituabbrevia-tions) that can be used when typing the command.
For complete information on command abbreviations, refer to the MS-DOS Reference Guide.
U sing a Simple Command
The d i r command is an example of a command that can be exe-cuted using only the command name. It is used to list the names of the files and directories in the current directory. Files and direc-tories are discussed in more detail in the sections entitled "USING AND NAMING FILES" and "FILE SYSTEMS AND DIRECTORIES" .
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Displays information about the files and directories in the specified drive and directory. If no drive or path is specified, list all files and directories in the current directory on the default drive.
/w Display the names of all files and directories in the current directory, listed across the screen. entries in the current directory.
If you type d i r at the prompt the system displays information
VP/ix and MS-DOS Primer - Release 1.1.0 19 After issuing a command, you may be instructed to provide more information. Usually the command provides a description of the appropriate responses.
When the instruction Press any key appears, you may press any letter of the alphabet (a - z), number ( 0 -9 ), or the
I
SPACEBARI
key.Command Arguments
An argument gives the system information that is required to pro-cess a specific command or to change the default, or standard, behavior of a command. DOS command arguments usually include the following components:
drive: Disk drive name. A disk drive is either a fixed disk drive or a diskette drive. Fixed disk and diskette drives are sometimes referred to as source drives and target or destination drives. A source drive is the drive from which you will be transferring information.
A destination drive is the drive to which you will be transferring information.
file name The name of a document or collection of information stored on the computer, including the file name exten-sion, if one exists. The file name extension is a suffix of one to three characters, separated from the file name by a period (.). The file name option never refers to the name of a device or a drive. You must include the file name extension when referring to a file that has a file name extension. File names are dis-cussed in more detail in the section entitled "USING AND NAMING FILES."
path name The sequence of directory and file names that de-scribes the location of a file or directory on the sys-tem. The path name of a file follows the general format:
\directory\directory\filename
Path names are discussed in greater detail in the sec-tion entitled "FILE SYSTEMS AND DIRECTORIES."
20 strings
VPjix and MS-DOS Primer - Release 1.1.0 Strings of text that are specific to a command and give the DOS system additional information.
Some commands require one or more arguments; arguments are names of all the files and directories in that directory:
VP/ix Z: \.usr\'tony> dir letters
VP/ix and MS-DOS Primer - Release 1.1.0 21 different from the UNIX system. UNIX options begin with a dash ( -). Some DOS commands accept both arguments and options.
For example, the d i r command can be used with the /w or "wide"
option, which displays the names of the files and directories in columns across the display. If you type:
VP/ix c: '\> d i r /w
then the screen wi11look similar to this:
Volume in drive C is DOS Directory of C:'\
COMMAND COM BACKUP EXE CHKDSK EXE MODE EXE 4 File(s) 232608 bytes free
Stopping Commands
You can permanently stop commands while they are running by using
I
CfRLI
and typing c.When commands produce a large amount of output on the screen, the display automatically scrolls to the next screen. Use
I
CfRLI
and type 5 to suspend the scrolling. UseI
CTRLI
and type q to resume scrolling.22 VPjix and MS-DOS Primer - Release 1.1.0