rosinstall generates setup.bash for bash users. If you are using a different shell this likely will not work for you. Please see below for options for other shells.
setup.zsh is created next to setup.bash and provides the same functionality.
setup.sh is created next to setup.bash and only sets the environment variables, without the convenience functions.
If you have a preferred shell and would like to add support we'd love to integrate a patch to support more shells.