China DOS Union

### Using Scripts to Set Global Environment Variables

Recently, I've noticed that many people are discussing how to use scripts to set system global environment variables that are long - term and effective. Coincidentally, I've also used this kind of content recently, so I've collected and sorted out everyone's discussion content, and thus this article is formed.

1. Internal tools: regedit /s, echo >> & regedit /s, reg add
2. External tools: setx, setntenvar, winset
3. Other scripts: vbs
4. Automatic batch processing: autoexec.bat, autoexec.nt

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1. Internal tools: regedit /s, echo >> & regedit /s, reg add

1.1 regedit /s - Windows built - in tool

Advantages: Can be used under all Windows systems, and can operate other registry items simultaneously
Disadvantages: Cannot dynamically define variables, needs to be restarted to take effect, and needs to read additional registry files

:: dsc.reg already exists and is available
REGEDIT /S DSC.REG

1.2 echo >> & regedit /s - Windows built - in commands and tools

Advantages: Can dynamically define variables, can be used under all Windows systems, and can operate other registry items simultaneously
Disadvantages: Needs to be restarted to take effect, and needs to read and write additional registry files

:: dsc.reg already exists and is available, modify the environment variable Driver to the converted value of the cd variable
ECHO "Driver"="%cd:\=\\%\\sqora32.dll">>DSC.REG
REGEDIT /S DSC.REG

1.3 reg add - Windows 2K/XP/03 built - in tool

Advantages: Can dynamically define variables
Disadvantages: Needs to be restarted to take effect, and cannot be used under 9X by default

SET ENV_POOL=HKLM\SYSTEM\ControlSet001\Control\Session Manager\Environment
REG ADD "%ENV_POOL%" /V PATH /T REG_SZ /D "%cd%;%Path%" /F >nul

2. External tools: setx, setntenvar, winset

2.1 setx - Support tool package extracted from 2K/XP/03 installation disc

Version 1.0a (5/31/96)
Gary Milne - Microsoft MCS

Advantages: Can dynamically define variables, takes effect immediately without restart, can dynamically reference variables, and can reference text content to set variables
Disadvantages: Can only be used under NTs, cannot delete variables but can only set them to empty values

:: Set current user global variable
SETX MACHINE COMPAQ
:: Set system global variable
SETX MACHINE "COMPAQ COMPUTER" -m
:: Static reference to other environment variables (only reference the current session environment variables once)
SETX MYPATH %PATH%
:: Dynamic reference to other environment variables (always reference the global environment variables)
SETX MYPATH ~PATH~
:: Use registry value to set environment variable
SETX BUILD -k "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\CurrentBuildNumber"
:: Use the content specified in the file to set environment variable (will not take effect immediately)
SETX IPGATEWAY -f ipconfig.out -r 0,7 "Gateway"

2.2 setntenvar - From Wuyou Boot Forum (topic = 4197) Lx1638 (Lao Jiu)

SetNTEnVar V06.04

Advantages: Can dynamically define variables, can define the CD - ROM drive letter as an environment variable, takes effect immediately without restart
Disadvantages: Can only be used under NTs

:: Modify variable
SETNTENVAR PATH=%PATH_BAK%
:: Delete variable
SETNTENVAR BAK_PATH=
:: Define CD - ROM drive letter as environment variable CDROM\CDROM0\CDROM1, etc.
SETNTENVAR /FindCDROM

2.3 winset - From 9x installation disc support tool package

Advantages: Can dynamically define variables, takes effect immediately without restart
Disadvantages: Can only be used under 9X, and runs in error under NTs

:: Modify variable
WINSET PATH=%PATH_BAK%
:: Delete variable
WINSET BAK_PATH=

3. Other scripts: vbs

3.1 vbs - From China DOS Union Forum (tid = 27952) electronixtar

set sysenv=CreateObject("WScript.Shell").Environment("system") 'Array object of system environment variables
sysenv.Remove("ztest2") 'Delete variable
sysenv("ztest3")="test value" 'Add variable

Advantages: Can dynamically define variables, takes effect immediately without restart
Disadvantages: Needs to modify the system configuration file, and is only valid for the command line created by command

4. Automatic batch processing: autoexec.bat, autoexec.nt

4.1 autoexec.bat - From the root directory of the system disk

Advantages: Can dynamically define variables, can be used under all DOS/Windows systems
Disadvantages: Needs to be restarted to take effect, and needs to modify the system file

echo set path=d:\batch;%path%>> c:\autoexec.bat

In 2K/XP/03, whether the variables in autoexec.bat are parsed is related to the following registry item

User Key:
Value Name: ParseAutoexec
Data Type: REG_SZ (String Value)
Value Data: (0 = disabled, 1 = enabled)

4.2 autoexec.nt - From %SystemRoot%\system32 of 2K/XP/03 system

Advantages: Can dynamically define variables, takes effect immediately without restart
Disadvantages: Needs to modify the system file, and is only valid for the command line that uses the autoexec.nt file in 2K/XP/03

echo set path=d:\batch;%path%>> %SystemRoot%\System32\autoexec.nt

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Generally speaking, there are two places for system environment variables under the NT series registry:

1. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment
Registry item representing the system environment variable space

2. HKEY_CURRENT_USER\Environment
Registry item representing the current user's environment variable space

The registry values under these two keys respectively represent the corresponding environment variables. Directly modifying the variables in the system space requires restarting to take effect globally, and for the variables modified in the user space, it is only necessary to log off.

In addition, it should be noted that the system variables set by the above methods cannot take effect in the current session (window) where the batch processing or command line is run. So if you query immediately after setting the variables, there will be no change.

The simplest way to solve this problem is to set the session - level variable to the same content as the system - level variable while setting the system - level variable. In addition, you can also use reg query or regedit /e or setx -k to query the corresponding registry value.

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About the issue of the autoexec.nt file

The effectiveness of the configuration file has nothing to do with the file name. It only takes effect when it can be correctly referenced by the command line program.

The method to reference the configuration file is to create a shortcut, fill in command in the item, click OK to generate the program information file (.pif) "MS - DOS mode", and define the initialization file in "Properties -> Program -> Advanced"

But because command.com always uses %SystemRoot%\_default.pif as the program information file, and _default.pif defines auotexec.nt and config.nt as the initialization configuration files, so when using command.com to open the command line, it can always successfully reference the environment variables set in autoexec.nt.

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Related links

1. setx.exe extracted from the support tool package of WinXP SP2
http://www.cn-dos.net/forum/viewthread.php?tid=28698

2. setx.vbs system environment variables that still take effect after restart
http://www.cn-dos.net/forum/viewthread.php?tid=27952

3. How to write a script to automatically add system environment variables
http://www.cn-dos.net/forum/viewthread.php?tid=24114

4. How to use batch processing to modify the system path environment variable
http://www.cn-dos.net/forum/viewthread.php?tid=25057

5. How to use batch processing to set the environment variables of the XP system
http://www.cn-dos.net/forum/viewthread.php?tid=23409

6. Mutual influence of various factors during the startup process of MSDOS7.10
http://www.cn-dos.net/forum/viewthread.php?tid=17107

16:56 2007 - 3 - 24
14:42 2007 - 4 - 1

[ Last edited by willsort on 2007 - 4 - 2 at 06:04 AM ]

Sofa!
Brother wil has finally posted a technical post again. Hehe

"Global environment variables" is it that a variable can be used in any CMD window???

Big beard, I also wrote one
http://www.cn-dos.net/forum/viewthread.php?tid=28204&fpage=1&highlight=%2Beverest79

First, admire willsort, then read the post

My XP SP2 c:\autoexec.bat content is empty;

It seems that wmic is more convenient for setting global variables;

Because I just happened to be looking at this recently

Willsort's post, arrived late, pay homage～～

The moderator's move is to come up with something practical right away..

Flying knife, another flying knife! willsort has been in seclusion for many days. This time, coming back to the arena, he has brought many surprises to everyone again. First, I'll give a thumbs up.

set sysenv=CreateObject("WScript.Shell").Environment("system") 'Array object for system environment variables
sysenv.Remove("ztest2") 'Delete variable
sysenv("ztest3")="test value" 'Add variable

This is borrowed. Thanks a lot