Windows 2000 Administration in a Nutshell

Name

environment variable

Synopsis

A string that contains information used to control some aspect of the operating system or applications.

Description

Environment variables contain information such as the path to an important system file or directory, the number and type of processors on the motherboard, and so on. Windows 2000 Server makes use of two types of environment variables:

User variables

These differ for each user who logs on to the computer, and users can create and modify their own user variables and assign them values. By default, Windows 2000 Server creates the user variables listed in Table 3.13.

Table 3-13. User Environment Variables

Variable	Description	Default Value
TEMP	Path to the user’s temporary directory	%USERPROFILE%\Local Settings\Temp
TMP	Path to the user’s temporary directory	%USERPROFILE%\Local Settings\Temp

System variables

These are the same for all users who log on to the computer, and their effect applies to the whole operating system. Only members of the Administrators group can create or modify system variables. The default system variables are listed in Table 3.14.

Table 3-14. System Environment Variables

Variable	Description	Default value
ComSpec	Path to command interpreter	%SystemRoot%\system32\cmd.exe
NUMBER_OF_PROCESSORS	Number of processors on the motherboard	Reflects actual number of processors in system
OS	Operating system installed	Windows_NT
OS2LibPath	Path to OS/2 library	%SystemRoot%\system32\os2\dll
Path