Using Command-Prompt Functions and Utilities

Using Command-Prompt Functions and Utilities

Although most computer users seldom use the command prompt available in all versions of Windows covered on the A+ Certification Exams, it's very important for technicians to know how to use the major command-prompt functions and programs. Command-prompt functions and programs can be used to

• Recover data from systems that can't boot normally.

• Reinstall lost or corrupted system files.

• Print file listings (believe it or not, you can't do this in Windows Explorer or My Computer!).

• Copy, move, or delete data.

• Display or configure certain operating system settings.

The following sections discuss the major command-prompt functions and utilities in more detail.

Starting a Command-Prompt Session

You can start a command-prompt session in Windows by clicking on the Command prompt or MS-DOS prompt option in the Start menu; it's usually located in the Accessories menu on most versions of Windows. However, it's faster to use the Run command:

1. Click Start, Run.

2. With Windows 9x/Me

   Type command and click OK.

   With Windows NT 4.0/2000/XP

   Type cmd and click OK.

caution

Before Windows XP, Search & Find searched all types of files for specified text. However, as initially shipped, Windows XP's Search tool excludes many types of files. Service Pack 1 partially fixes this behavior, as does the Windows XP Application Compatibility Update, October 25, 2001. (Both are available from Windows Update.) To search all file types, you also need to use the Indexing Service and enable the option to index files with unknown extensions. For more information about this problem and its solutions, see Microsoft Knowledge Base article 309173.

Internal Commands Overview

Command.com (Windows 9x/Me) and Cmd (Windows NT 4.0/2000/XP) contain the internal commands listed in Table 18.7. Commands marked (RC) can also be used by the Windows 2000/XP Recovery Console.

Table 18.7. Major Internal Commands

Internal Command	Category	Use	Example
DATE	System management	Views system current date and allows it to be changed	DATE
TIME	System management	Views system current time and allows it to be changed	TIME
COPY [1] (RC)	Disk management	Copies one or more files to another folder or drive	COPY *.* A:\
DEL [1] (RC)	Disk management	Deletes one or more files on current or specified folder or drive	DEL *.TMP
ERASE [1] (RC)	Disk management	Same as DEL	ERASE *.TMP
DIR [1] (RC)	Disk management	Lists files on current or specified folder or drive	DIR *.EXE
MD [1] (MKDIR) (RC)	Disk management	Makes a new folder (subdirectory)	MD TEMP
CD [1] (CHDIR) (RC)	Disk management	Changes your current location to the specified folder (subdirectory)	CD TEMP
RD [1] (RMDIR) (RC)	Disk management	Removes an empty folder	RD TEMP
RENAME (REN) [1]	Disk management	Renames a file	REN joe.txt jerry.txt
VER [1]	System management	Lists the version of operating system in use	VER
VOL	Disk management	Lists the current volume label and serial number for the default drive	VOL
SET [1]	System management	Used to set options for a device or program; SET without options displays all current SET variables	SET TEMP=C:\TEMP
PROMPT	System management	Sets display options for the command prompt	PROMPT=$P $G (displays drive letter followed by greater-than sign)
PATH	System management	Sets folders or drives that can be searched for programs to be run	PATH=C:\DOS;C:\WINDOWS
ECHO [1]	Batch files	Turns on or off the echo (display) of commands to the screen	ECHO OFF
CLS (RC)	Batch files, system management	Clears the screen of old commands and program output	CLS
LH (LOADHIGH)	Memory management (Windows 98)	Loads TSR programs above 640K (see preceding memory-management discussion)	LH C:\MOUSE\MOUSE.COM
TYPE [1] (RC)	System management	Views text files onscreen	TYPE AUTOEXEC.BAT

^[1] See the Windows Command Reference on the CD for details and syntax .

Because these commands are built into the command interpreter, they can also be used from the command prompt if you boot the computer with the Windows 9x/Me Emergency Boot Disk. All but LH (Loadhigh) can also be run from the Windows 2000/XP command prompt.

You can also use command to create a command prompt in Windows NT 4.0/2000/XP. This mode is sometimes referred to as Windows DOS; it is used automatically if you run a DOS program within these versions of Windows. However, creating a command prompt with command is not recommended for most situations because you cannot use the enhancements to internal or external commands available with cmd .

Using Wildcards to Specify a Range of Files

Command-prompt functions and utilities can be used to operate on a group of files with similar names by using one of the following wildcard symbols:

• ? replaces a single character.

• * replaces a group of characters .

For example, DIR *.EXE displays files with the .EXE extension in the current folder (directory). DEL MYNOVEL??.BAK removes the following files: MYNOVEL00.BAK , MYNOVEL01.BAK , but not MYNOVEL.BAK .

Windows Command-Prompt Utilities

Command-prompt utility programs are found in these locations in Windows 9x/Me:

• C:\Windows\Command

• The Windows 9x/Me Emergency Startup Disk (also called the Emergency Boot Disk [EBD] or Startup disk)

tip

To get help for any internal or external command-prompt function or program, type the program name followed by /? . For example, DIR/? displays help for the DIR command.

For more information about the Windows 9x Emergency Startup Disk, see "Creating a Boot Disk Suitable for Hard Disk Preparation," p. 484 .

Most of these commands can also be run from the Windows NT/2000/XP command prompt or from the Windows 2000/XP Recovery Console, which can be started from the Windows CD-ROM or can be installed to the hard disk for troubleshooting startup problems.

These utilities are also referred to as external commands because, unlike the built-in commands stored in Command.com or Cmd , each of these are separate programs.

Windows NT/2000/XP's command-prompt utilities are typically found in the System32 folder beneath the default Windows folder.

Table 18.8 lists the major command-prompt utilities supplied with Windows, how each is used, and whether it is part of the Windows 98 Emergency Boot Disk, Windows 95 Startup disk, or the Windows 2000/XP Recovery Console.

Table 18.8. Major Windows Command-Prompt Utilities

Utility	How Used	Supported at Command Prompt by Windows Versions	Windows 98 EBD	Windows 2000/XP Recovery Console
ATTRIB.EXE [2]	Changes file attributes	All	Yes [1]	Yes
CHKDSK.EXE	Simple disk repair and statistics reporting tool ( replaced by ScanDisk in Windows 98)	All	Yes [1]	Yes
CVT.EXE	Converts FAT16 drive to FAT32 file system	98, Me		N/A
DEBUG.EXE	Debugging utility	All	Yes [1]	No
DELTREE.EXE [2]	Deletes folders and files contained in folders	98, Me		N/A
EXTRACT.EXE	Used to manually uncompress files from Windows .CAB compressed archives	All	Yes	N/A
EXPAND.EXE	Used to manually extract files from Windows .CAB archive files	NT, 2000, XP	N/A	Yes
FDISK.EXE	Partitions hard disks	9x, Me	Yes	N/A
MEM.EXE [2]	Displays overall memory usage and programs in conventional memory	All	No	No
MOVE.EXE	Moves files from one location to another	All	No	No
MSCDEX.EXE [2]	Provides access to CD-ROM drives after CD-ROM device drive is loaded in Config.sys	9x, Me (EBD)	Yes [1]	N/A
SCANDISK.EXE	Disk repair and disk statistics tool (replaces CHKDSK )	9x, Me	Yes [1]	N/A
SCANREG.EXE	Registry repair tool	98, Me	No	N/A
UNINSTAL.EXE	Uninstalls Windows 98	98	Yes [1]	N/A
xcopy.exe [2]	Faster version of COPY that can create folders and copy files based on many different criteria	All	No	No
xcopy32.exe [2]	Used in place of standard Xcopy when run from a DOS Window while the Windows 9x/Me GUI is active; supports long filenames and additional options	9x, Me	No	N/A
DISKCOPY.COM	Makes a bit-by-bit exact copy of a diskette	All	No	No
DOSKEY.COM	Enables user to cycle through previous command-prompt commands for reuse	All	No	Not necessary
EDIT.COM [2]	DOS-based text editor	All	Yes [1]	No
FORMAT.EXE	High-level formatter for hard and floppy drives	All	Yes [1]	Yes
SYS.COM	Transfers system files to formatted hard or floppy drives	9x, Me	Yes [1]	N/A
SETVER.EXE [2]	Enables older software to run without triggering an "incorrect MS-DOS version" error	9x, NT, 2000, XP	No	N/A

^[2] For more details and command syntax, see the Windows Command Reference on the CD packaged with this book

^[1] Extracted to RAMDISK created when EBD is used to start computer

Windows 95's Startup disk contains all the Windows 98 EBD files listed in the table except for Debug and Mscdex . You can copy these files manually from the \Windows\System folder to the Startup disk if needed.

For more information about the Windows 2000/XP Recovery Console, see "Windows Recovery Console," in Chapter 20.

The command-prompt utilities listed in Table 18.9 are part of Windows NT 4.0/2000/XP only. For a more complete list, type HELP from the Windows NT/2000/XP command prompt. To see command options, type /? after each command.

Table 18.9. Windows NT/2000/XP-Only Command-Prompt Utilities

Utility	How Used
Assoc	Displays or changes file extension associations
At	Schedules the running of commands or programs
Cacls	Displays or changes access control lists (ACLs) of files
Chkntfs	Displays or changes the operation of Chkdsk at startup time
Compact	Displays or changes the current compression status of files on NTFS partitions only
Convert	Converts FAT partitions other than the current drive to NTFS
Ftype	Displays or changes file types used in file extension associations
Title	Sets window title for a command-prompt ( CMD.EXE ) session

Getting Help with a Particular Command

Most command-line functions and utilities provide you with concise help for options; type the command name followed by /? to see options for that command.

tip

Most Windows 9x command-prompt commands and utilities have similar options to those used by MS-DOS 6.x. The MS-DOS 6.x Help file (which contains more detailed help and examples than those provided by /? help) is stored on the Windows 9x CD-ROM in the OldMSDOS folder. To view the help file, switch to that folder and open Help.com .