Build Working Directory
The build working directory is the directory set as current for the build process. By default, this is the same directory as the Build Checkout Directory.
If a build script needs to run from a location other than the checkout directory, you can specify the location explicitly using the Working Directory field of the Advanced options in the Build Runner settings.
The path entered in the Working Directory field can be either absolute or relative to the build checkout directory. When using this option, all of the other paths should still be entered relative to the checkout directory.
Concepts: Build Checkout Directory