Overcoming the 1024 character limit with setx

Question

I am trying to set environment variables using the setx command, such as follows

setx PATH "f:\common tools\git\bin;f:\common tools\python\app;f:\common tools\python\app\scripts;f:\common tools\ruby\bin;f:\masm32\bin;F:\Borland\BCC55\Bin;%PATH%"

However, I get the following error if the value is more then 1024 characters long:

WARNING: The data being saved is truncated to 1024 characters.

SUCCESS: Specified value was saved.

But some of the paths in the end are not saved in variable, I guess due to character limit as the error suggests.

Answer 1

Your best bet is to edit the registry directly.

Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment and edit the Path value (then reboot to activate the new value).

Note however that while you can enter a very long path, (up to the maximum environment variable length; 2,048 or 32,768 bytes depending on the source), not all software will be able to read and handle it correctly if it is too long.

Answer 2

This open-source SetEnv command-line tool is good to edit the PATH and other environment variables without limitations. It uses a dynamic buffer so no static limitations like 1024.

http://www.codeproject.com/Articles/12153/SetEnv

The choice of a % as a prefix to append to a variable could have been better though, as makes the syntax difficult sometimes if used with other batch local variables...

Answer 3

You could use a PowerShell script similar to the following:

$newPath = 'f:\common tools\git\bin;f:\common tools\python\app;f:\common tools\python\app\scripts;f:\common tools\ruby\bin;f:\masm32\bin;F:\Borland\BCC55\Bin'
$oldPath = [Environment]::GetEnvironmentVariable('path', 'machine');
[Environment]::SetEnvironmentVariable('path2', "$($newPath);$($oldPath)",'Machine');

The Environment.SetEnvironmentVariable() API call will broadcast WM_SETTINGCHANGE so you do not need to reboot.

Answer 4

A far superior tool than setx for path manipulation is pathed.exe. Unfortunately, it's limited to editing the path.

In addition to a superior user experience than setx, you don't have a 1024 character limit. Unlike direct registry manipulation, this application uses the Environment.SetEnvironmentVariable() API call which will broadcast WM_SETTINGCHANGE.