How do I add to the Windows PATH variable using setx? Having weird problems

I want to modify the Windows PATH variable using setx. The following works at least 50% of the time on Windows 8:

setx PATH %PATH%;C:\Python27\;C:\Python27\Scripts\

If it gives the error "the default argument can only be used 2 times", then the following works some of the time:

setx PATH "%PATH%;C:\Python27\;C:\Python27\Scripts\"

The difference is that we wrapped the second argument in quotes. I believe the quotes are necessary when %PATH% expands to include spaces.

However, I have encountered some weird problems on Windows 7. On one particular Windows 7 machine, I had this problem:

echo %PATH%

It prints:

C:\Foo\;C:\Bar\;[...lots of stuff...]C:\Baz\

Then I do this:

setx PATH "%PATH%;C:\Quux\"

Then it says "Error: Truncated at 1,024 characters." Now let's check what PATH contains:

echo %PATH%

It prints:

C:\Foo\;C:\Foo\;C:\Bar\;C:\Bar\;[...lots of stuff, now duplicated...]C:\B

...and it is cut off at 1,024 characters. It ran over because of the duplicates. Also interesting: The value of PATH changes despite the fact that setx raised an error and did not say "Success".

I was able to repeat this strange behavior several times (luckily I had saved the original contents of PATH).

At the moment, the only surefire way I know to append to the PATH is the following:

1. echo the PATH.

2. Copy the contents of PATH into a text file and manually add ;C:\Python27\;C:\Python27\Scripts\ to the end of the PATH.

3. Copy the whole thing out of the text file.

4. setx PATH "<paste the string here>"

That process works every single time on both Windows 7 and Windows 8.

I should really be able to do this in one command. What am I doing wrong?

Run cmd as administrator, then:

setx /M PATH "%PATH%;<your-new-path>"

The /M option sets the variable at SYSTEM scope. The default behaviour is to set it for the USER.

TL;DR

The truncation happens because when you echo %PATH% you get the concatenation of SYSTEM and USER values so, when you add it in your second argument to setx, the command will try to fit the contents of both SYSTEM and USER within the USER var. When you echo again, the result will be doubled.

The /M option requires administrator privilege, so you need to open your terminal with "run as administrator" otherwise setx will fail with "access to registry path is denied".

Note: You won't see the new value when you echo %PATH% just after setting it this way, you need to close cmd and open again.

If you want to check the actual values stored in registry check this question.

This works perfectly:

for /f "usebackq tokens=2,*" %A in (`reg query HKCU\Environment /v PATH`) do set my_user_path=%B

setx PATH "C:\Python27;C:\Python27\Scripts;%my_user_path%"

The 1st command gets the USER environment variable 'PATH', into 'my_user_path' variable The 2nd line prepends the 'C:\Python27;C:\Python27\Scripts;' to the USER environment variable 'PATH'

If someone want to run it in PowerShell it works like below,

Run Powershell as Administrator

Then

setx /M PATH "$Env:PATH;<path to add>"

To verify, open another Powershell and view PATH as below,

$Env:PATH

If you're not beholden to setx, you can use an alternate command line tool like pathed. There's a more comprehensive list of alternative PATH editors at https://superuser.com/questions/297947/is-there-a-convenient-way-to-edit-path-in-windows-7/655712#655712

You can also edit the registry value directly, which is what setx does. More in this answer.

It's weird that your %PATH% is getting truncated at 1024 characters. I thought setx didn't have that problem. Though you should probably clean up the invalid path entries.

Without admin rights the only way that worked for me is a bat file that contains the following code:

for /F "tokens=2* delims= " %%f IN ('reg query HKCU\Environment /v PATH ^| findstr /i path') do set OLD_SYSTEM_PATH=%%g
setx PATH "%USERPROFILE%\wev-tools;%OLD_SYSTEM_PATH%"

The code is the combination of the answers https://stackoverflow.com/a/45566845/4717152 and https://stackoverflow.com/a/10292113/4717152

Sadly with OOTB tools, you cannot append either the system path or user path directly/easily. If you want to stick with OOTB tools, you have to query either the SYSTEM or USER path, save that value as a variable, then appends your additions and save it using setx. The two examples below show how to retrieve either, save them, and append your additions. Don't get mess with %PATH%, it is a concatenation of USER+SYSTEM, and will cause a lot of duplication in the result. You have to split them as shown below...

Append to System PATH

for /f "usebackq tokens=2,*" %A in (`reg query "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v PATH`) do set SYSPATH=%B

setx PATH "%SYSPATH%;C:\path1;C:\path2" /M

Append to User PATH

for /f "usebackq tokens=2,*" %A in (`reg query HKCU\Environment /v PATH`) do set userPATH=%B

setx PATH "%userPATH%;C:\path3;C:\path4"

I was facing the same problems and found a easy solution now.

Using pathman.

pathman /as %M2%

Adds for example %M2% to the system path. Nothing more and nothing less. No more problems getting a mixture of user PATH and system PATH. No more hardly trying to get the correct values from registry...

Tried at Windows 10

setx path "%PATH%; C:\Program Files (x86)\Microsoft Office\root\Office16" /m

This should do the appending to the System Environment Variable Path without any extras added, and keeping the original intact without any loss of data. I have used this command to correct the issue that McAfee's Web Control does to Microsoft's Outlook desktop client.

The quotations are used in the path value because command line sees spaces as a delimiter, and will attempt to execute next value in the command line. The quotations override this behavior and handles everything inside the quotations as a string.

Just wanted to reiterate: the earlier answer from Manohar Reddy Poreddy is the correct one.

There are a number of improvements that can be made, that I thought might be helpful to share:

@echo off

REM -- Use directory where script is located. For current working directory, use %CD%
set CURRENT_DIR=%~dp0
REM -- Great example from Strawberry Perl's portable shell launcher:
if #%CURRENT_DIR:~-1%# == #\# set CURRENT_DIR=%CURRENT_DIR:~0,-1%

REM -- Load the user PATH from the registry, making sure it is not blank
reg query HKCU\Environment /v PATH 1>nul 2>&1
if ERRORLEVEL 1 goto skipLoadPath
for /f "usebackq tokens=2,*" %%A in (`reg query HKCU\Environment /v PATH`) do set MY_USER_PATH=%%B

REM -- Optionally, checks if this directory is already part of the user PATH
REM -- This will avoid duplication, and allow this to be run multiple times,
REM -- but if a sub-directory of the current is already part of the user PATH,
REM -- this script will simply not do anything
echo %MY_USER_PATH%|find "%CURRENT_DIR%" >nul
if errorlevel 1 (goto skipLoadPath) else (goto skipSetXPath)
:skipLoadPath

REM -- Avoid adding a useless semicolon to the previous user PATH
if not "" == "%MY_USER_PATH%" set "MY_USER_PATH=%MY_USER_PATH%;"
REM -- Permanently set the following location as part of the system path
setx PATH "%MY_USER_PATH%%CURRENT_DIR%" >nul 2>&1
REM -- This will update the current environment, since SETX only updates the registry
set "PATH=%PATH%;%MY_USER_PATH%%CURRENT_DIR%"
:skipSetXPath

Steps: 1. Open a command prompt with administrator's rights.

Steps: 2. Run the command: setx /M PATH "path\to;%PATH%"

[Note: Be sure to alter the command so that path\to reflects the folder path from your root.]

Example : setx /M PATH "C:\Program Files;%PATH%"

I was having such trouble managing my computer labs when the %PATH% environment variable approached 1024 characters that I wrote a Powershell script to fix it.

You can download the code here: https://gallery.technet.microsoft.com/scriptcenter/Edit-and-shorten-PATH-37ef3189

You can also use it as a simple way to safely add, remove and parse PATH entries. Enjoy.

This vbscript/batch hybrid "append_sys_path.vbs" is not intuitive but works perfectly:

If CreateObject("WScript.Shell").Run("%ComSpec% /C ""NET FILE""", 0, True) <> 0 Then
	CreateObject("Shell.Application").ShellExecute WScript.FullName, """" & WScript.ScriptFullName & """", , "runas", 5
	WScript.Quit
End If
Set Shell = CreateObject("WScript.Shell")
Cmd = Shell.Exec("%ComSpec% /C ""REG QUERY ""HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"" /v Path | FINDSTR /I /C:""REG_SZ"" /C:""REG_EXPAND_SZ""""").StdOut.ReadAll
Cmd = """" & Trim(Replace(Mid(Cmd, InStr(1, Cmd, "_SZ", VBTextCompare) + 3), vbCrLf, ""))
If Right(Cmd, 1) <> ";" Then Cmd = Cmd & ";"
Cmd = "%ComSpec% /C ""REG ADD ""HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"" /v Path /t REG_EXPAND_SZ /d " & Replace(Cmd & "%SystemDrive%\Python27;%SystemDrive%\Python27\Scripts"" /f""", "%", """%""")
Shell.Run Cmd, 0, True

Advantages of this approach:

1. It doesn't truncate the system path environment at 1024 characters.
2. It doesn't concatenate the system and user path environment.
3. It's automatically run as administrator.
4. Preserve the percentages in the system path environment.
5. Supports spaces, parentheses and special characters.
6. Works on Windows 7 and above.