The "sync" command:

Usage: fossil sync ?URL? ?options?

Synchronize the local repository with a remote repository.  This is
the equivalent of running both "push" and "pull" at the same time.
Use the "-R REPO" or "--repository REPO" command-line options
to specify an alternative repository file.

If a user-id and password are required, specify them as follows:

    http://userid:password@www.domain.com:1234/path

If the URL is not specified, then the URL from the most recent successful
clone, push, pull, remote-url, or sync command is used.

The URL specified normally becomes the new "remote-url" used for
subsequent push, pull, and sync operations.  However, the "--once"
command-line option makes the URL a one-time-use URL that is not
saved.

Use the --private option to sync private branches with the
remote repository.

See also:  clone, push, pull, remote-url