Question

Sometimes I have a batch file like this:

Action.bat:

Set PATH=%PATH%;C:\Some\Folder\I\Need

foo.exe Bar1
foo.exe Bar2
foo.exe Bar3
@Rem Etc...

where foo.exe is a program that expects PATH to contain a certain directory.

Then I decide to use it for — guess what? — batch processing:

For /R %%f In (*) Do Call Action.bat "%%~f"

Now when I run this, PATH easily overflows.

What is the proper way to prevent this kind of overflow?

Answer 1

Use SETLOCAL:

@ECHO OFF
SETLOCAL
SET PATH=%PATH%;C:\Some\Folder\You\Need

foo.exe Bar1
…
:: ENDLOCAL is implied at the end of the script, but you can add it explicitly
ENDLOCAL

All the changes to environment variables within the scope of SETLOCAL are, well, local. That is, they are discarded upon executing ENDLOCAL.