def command_umount_all(self):
has_failed = False<EOL>for system_id in self.environment.get_mounted_ids():<EOL><INDENT>try:<EOL><INDENT>system = SystemModel.create_by_id(system_id, self.environment)<EOL>controller = SystemControllerModel(system, self.environment)<EOL>controller.unmount()<EOL><DEDENT>except SftpConfigException as e:<EOL><INDENT>sys.stderr.write('<STR_LIT>' % (system_id, str(e)))<EOL>has_failed = True<EOL><DEDENT><DEDENT>sys.exit(<NUM_LIT:0> if not has_failed else <NUM_LIT:1>)<EOL>
Unmounts all sftp file systems known to sftpman.
        Usage: sftpman umount_all