SETX doesn't append path to system path variable

问题

I have tried below command to append some path to system path variable by batch-file :

setx PATH "%PATH%;C:\Program Files\MySQL\MySQL Server 5.5\bin"

I have checked system variable path after running above batch-file, above path isn't in there.

You can see all windows Variable value content in below :

C:\Program Files (x86)\AMD APP\bin\x86_64;C:\Program Files (x86)\AMDAPP\bin\x86;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\ProgramFiles (x86)\ATI Technologies\ATI.ACE\Core-Static;

What am i doing wrong?

回答1:

To piggy-back on @Endoro's answer (I lack the rep to comment):

If you want to change the system-wide environment variables, you have to use /M, a la:

setx PATH "%PATH%;C:\Program Files\MySQL\MySQL Server 5.5\bin" /M

setx.exe is picky about placement of the /M, BTW. It needs to be at the end.

回答2:

WARNING!

setx will truncate the value to 1024 characters.

If you use it to modify PATH you might mess up your system.

You can use this PowerShell snippet to add something to your path:

$new_entry = 'c:\blah'

$old_path = [Environment]::GetEnvironmentVariable('path', 'machine');
$new_path = $old_path + ';' + $new_entry
[Environment]::SetEnvironmentVariable('path', $new_path,'Machine');

In case you want to not re-add an already existing entry something like this will do (see for a better version further down):

$new_entry = 'c:\blah'
$search_pattern = ';' + $new_entry.Replace("\","\\")

$old_path = [Environment]::GetEnvironmentVariable('path', 'machine');
$replace_string = ''
$without_entry_path = $old_path -replace $search_pattern, $replace_string
$new_path = $without_entry_path + ';' + $new_entry
[Environment]::SetEnvironmentVariable('path', $new_path,'Machine');

Here a newer version that I'm using now (2017-10-23). This version handles nested paths correctly. E.g. it handles the case of PATH containing "c:\tool\foo" and you want to add "c:\tool".

$desired_entry = 'C:\test'

$old_path = [Environment]::GetEnvironmentVariable('path', 'machine');

$old_path_entry_list = ($old_path).split(";")
$new_path_entry_list = new-object system.collections.arraylist

foreach($old_path_entry in $old_path_entry_list) {
    if($old_path_entry -eq $desired_entry){
        # ignore old entry
    }else{
        [void]$new_path_entry_list.Add($old_path_entry)
    }
}
[void]$new_path_entry_list.Add($desired_entry)
$new_path = $new_path_entry_list -Join ";"

[Environment]::SetEnvironmentVariable('path', $new_path,'Machine');

回答3:

you shouldn't look at the system environment variables but to your user environment variables:

回答4:

SETX /M Path "%PATH%;%ProgramFiles%\MySQL\MySQL Server 5.5\bin\

It will append your path to system variable

回答5:

Should never use setx for a path since it's limited to 1024 chars, as mentioned.

Could use reg add:

set pathkey="HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment"
for /F "usebackq skip=2 tokens=2*" %%A IN (`reg query %pathkey% /v Path`) do (reg add %pathkey% /f /v Path /t REG_SZ /d "%%B;C:\Program Files\MySQL\MySQL Server 5.5\bin")

or set pathkey="HKEY_CURRENT_USER\Environment" for user path.

Then to broadcast the change:

powershell -command "& {$md=\"[DllImport(`\"user32.dll\"\",SetLastError=true,CharSet=CharSet.Auto)]public static extern IntPtr SendMessageTimeout(IntPtr hWnd,uint Msg,UIntPtr wParam,string lParam,uint fuFlags,uint uTimeout,out UIntPtr lpdwResult);\"; $sm=Add-Type -MemberDefinition $md -Name NativeMethods -Namespace Win32 -PassThru;$result=[uintptr]::zero;$sm::SendMessageTimeout(0xffff,0x001A,[uintptr]::Zero,\"Environment\",2,5000,[ref]$result)}"

回答6:

I faced the same problem when i tried to add path variables related to fortran (Eclipse for c/c++/fortran)

I tried SETX /M Path "%PATH%;C:\Users\mahidhai\cygwin64\bin" in command prompt as administrator .I got warning saying data was truncated to 1024 characters and stored .

SOlution: Go to registry file directly. Run->regedit Navigate to Environment

(Entire path : HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment )

Click on path registry and add the path variable directly. Or remove any repeated path variables .

Now , open command prompt and then run the same command setx /M path "%path%, "

Path variable could be related to C or C++ or fortran

No worries in editing registry file , it will be saved permanently , don't be afraid as environment variables are in session manager.

来源：https://stackoverflow.com/questions/17240725/setx-doesnt-append-path-to-system-path-variable