wstool provides commands to manage several local SCM repositories (supports git, mercurial, subversion, bazaar) based on a single workspace definition file (.rosinstall). wstool replaces the rosws tool for catkin workspaces. As catkin workspaces create their own setup file and environment, wstool is reduced to version control functions only. So wstool does not have a "regenerate" command, and does not allow adding non-version controlled elements to workspaces. In all other respects, it behaves the same as rosws.