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I have to set environment variables on different windows machines, but I don't want to be bothered changing them manually by getting on the properties screen of "My Computer"

I want to do it from the command line, with a batch file. As far as I understand, using set will only change the variable for the processes I will call in the command window.

I want to set it definitely, so later, when running a new process, it will use those new settings I have set. Is there a way to do that from the command line?

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  • Whats the point of setting them from the command line if they are going permanent? You wont need to do it again. Commented May 5, 2011 at 13:10
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    Yes, but I have to do it on several computers, so running the script will save me some time. Commented May 5, 2011 at 13:19
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    Ok, in that case you can set your env on one computer and do an export of the entries described below and have a .reg file, if SETX isnt available to you. Commented May 5, 2011 at 13:23
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    RE: 'Whats the point of setting them from the command line...' Where I work there is a constant requirement to a number of persistent environmental variables to different values in order to test/develop different versions of the software. Licensing means it can't be done any other way (e.g. running a VM) so our only resort is to use SETX in a batch script. Using .reg is less good as its harder to document/see exactly what's going on Commented Jan 14, 2014 at 12:32

5 Answers 5

Reset to default
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Use the SETX command (note the 'x' suffix) to set variables that persist after the cmd window has been closed.

For example, to set an env var "foo" with value of "bar":

setx foo bar /m

Though it's worth reading the 'notes' that are displayed if you print the usage (setx /?), in particular:

  1. On a local system, variables created or modified by this tool will be available in future command windows but not in the current CMD.exe command window.

  2. On a remote system, variables created or modified by this tool will be available at the next logon session.

In PowerShell, the [Environment]::SetEnvironmentVariable command.

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10 Comments

It seems like SETX is only available on windows XP SP2
It worked on Windows 7 for me. What version of Windows are you using?
Take care with SETX, it truncate your variable length to 1024 char... very dangerous when manipulating %path%.
with Power Shell you can just [Environment]::SetEnvironmentVariable('PATH', "Whatever you need it to be", "Machine"), see msdn.microsoft.com/en-us/library/96xafkes(v=vs.110).aspx
Use /M to make it a system variable
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The MSDN documentation for environment variables tells you what to do:

To programmatically add or modify system environment variables, add them to the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the string "Environment". This allows applications, such as the shell, to pick up your updates.

You will of course need admin rights to do this. I know of no way to broadcast a windows message from Windows batch so you'll need to write a small program to do this.

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6 Comments

Ok, so considering your solution, I have created a registry (.reg) file containing the environment variables I want to add/change. I'll then run this file on all the target PCs. I don't really need to send a windows message, as I will just restart the application that will be impacted. Thanks.
I'm adding your other answer here, as it was exactly what I was looking for when I stumbled upon this question: stackoverflow.com/a/19705691/3543437
@David, So why not setx per below?
I think this reg has the advantage of not truncating and not being powershell
I found a powershell snippet that is said to perform the refresh for exactly this use case: stackoverflow.com/a/11622384/2699217
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:: Sets environment variables for both the current `cmd` window :: and/or other applications going forward. :: I call this file keyz.cmd to be able to just type `keyz` at the prompt :: after changes because the word `keys` is already taken in Windows. @echo off :: set for the current window set APCA_API_KEY_ID=key_id set APCA_API_SECRET_KEY=secret_key set APCA_API_BASE_URL=https://paper-api.alpaca.markets :: setx also for other windows and processes going forward setx APCA_API_KEY_ID %APCA_API_KEY_ID% setx APCA_API_SECRET_KEY %APCA_API_SECRET_KEY% setx APCA_API_BASE_URL %APCA_API_BASE_URL% :: Displaying what was just set. set apca :: Or for copy/paste manually ... :: setx APCA_API_KEY_ID 'key_id' :: setx APCA_API_SECRET_KEY 'secret_key' :: setx APCA_API_BASE_URL 'https://paper-api.alpaca.markets'
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This so vastly simplified my algorithm work efficiency and saved so much time I thought I'd share it case it might help someone (of those capable of comprehending it)
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Indeed SET TEST_VARIABLE=value works for current process only, so SETX is required. A quick example for permanently storing an environment variable at user level.

  1. In cmd, SETX TEST_VARIABLE etc. Not applied yet (echo %TEST_VARIABLE% shows %TEST_VARIABLE%,
  2. Quick check: open cmd, echo %TEST_VARIABLE% shows etc.
  3. GUI check: System Properties -> Advanced -> Environment variables -> User variables for -> you should see Varible TEST_VARIABLE with value etc.
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An example with VBScript (.vbs)

Sub sety(wsh, action, typey, vary, value) Dim wu Set wu = wsh.Environment(typey) wui = wu.Item(vary) Select Case action Case "ls" WScript.Echo wui Case "del" On Error Resume Next wu.remove(vary) On Error Goto 0 Case "set" wu.Item(vary) = value Case "add" If wui = "" Then wu.Item(vary) = value ElseIf InStr(UCase(";" & wui & ";"), UCase(";" & value & ";")) = 0 Then wu.Item(vary) = value & ";" & wui End If Case Else WScript.Echo "Bad action" End Select End Sub Dim wsh, args Set wsh = WScript.CreateObject("WScript.Shell") Set args = WScript.Arguments Select Case WScript.Arguments.Length Case 3 value = "" Case 4 value = args(3) Case Else WScript.Echo "Arguments - 0: ls,del,set,add; 1: user,system, 2: variable; 3: value" value = "```" End Select If Not value = "```" Then ' 0: ls,del,set,add; 1: user,system, 2: variable; 3: value sety wsh, args(0), args(1), UCase(args(2)), value End If
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4 Comments

You should consider adding some context or an explanation to accompany your code.
Powerful piece of code +1. Works on XP without setx (and without possibility to install it). Simple use (in my case): wsh.Environment("user").Item("myVar") = "my value"
Since no one has taken the trouble, to use on XP (no Resource Kit or setx required), to accomplish {set foo=bar} for all (other) DOS windows: 1. save above code as SetVar.vbs 2. setvar.vbs set system foo "bar" Note, the current DOS window does not get FOO from this. Issue set foo=bar to achieve that
Note also, this survives reboot (when you use the system parm)

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