This can be easily achieved by issuing a command like below:
$ /path/to/zato-binary/bin/py -m zato.server.main /path/to/server
For instance, if you've installed Zato to /opt/zato and a server to /home/user/server1, the full command will be
$ /opt/zato/bin/py -m zato.server.main /home/user/server1
Note that it can be shortened to the following one if you've followed the recommended installation steps and Zato binaries are on PATH
$ py -m zato.server.main /home/user/server1
Server started in such a way can be stopped using Ctrl-C as in the screenshots below.
Note that as an additional bonus, log levels will be in color when servers run in foreground.