_planBuilderConfig

'Environment Variables' (Optional) — Specify any additional* operating system environment variables you want to pass to your build; Please note, multiple variables must be separated with spaces, and parameters with spaces must be quoted (e.g 'ANT_OPTS=-Xms200m -Xmx700m'). You can also include Bamboo global or build-specific variables (see Using Global, Plan or Build-specific Variables).
* i.e. additional to the existing environment variables (see Viewing Bamboo's System Information for a list). Note that existing environment variables are automatically available to the executable, thus you don't need to specify them in the 'System Environment Variables' field.
'Working Sub Directory' (Optional) — A subdirectory relative to the Job build's root directory where Bamboo will execute your specified executable's commands. The Job build's root directory contains everything checked out from your Job's configured source repository. If you leave this field blank, Bamboo will look for the build files in the build root directory (which is assumed to be the Working Directory, as described in Locating Important Directories and Files). This option is useful, if your Task has a build script in a subdirectory and the executable needs to be run from within that subdirectory, in which case, you would type the name of that subdirectory in this field.

Bamboo 3.3 Documentation