The "update" command:

Usage: fossil update ?OPTIONS? ?VERSION? ?FILES...?

Change the version of the current checkout to VERSION. Any uncommitted changes are retained and applied to the new checkout.

The VERSION argument can be a specific version or tag or branch name. If the VERSION argument is omitted, then the leaf of the subtree that begins at the current version is used, if there is only a single leaf. VERSION can also be "current" to select the leaf of the current version or "latest" to select the most recent check-in.

If one or more FILES are listed after the VERSION then only the named files are candidates to be updated, and any updates to them will be treated as edits to the current version. Using a directory name for one of the FILES arguments is the same as using every subdirectory and file beneath that directory.

If FILES is omitted, all files in the current checkout are subject to being updated and the version of the current checkout is changed to VERSION. Any uncommitted changes are retained and applied to the new checkout.

The -n or --dry-run option causes this command to do a "dry run". It prints out what would have happened but does not actually make any changes to the current checkout or the repository.

The -v or --verbose option prints status information about unchanged files in addition to those file that actually do change.

Options:

--case-sensitive BOOL
Override case-sensitive setting
--debug
Print debug information on stdout
--latest
Acceptable in place of VERSION, update to latest version
--force-missing
Force update if missing content after sync
-n|--dry-run
If given, display instead of run actions
-v|--verbose
Print status information about all files
-W|--width WIDTH
Width of lines (default is to auto-detect). Must be more than 20 or 0 (= no limit, resulting in a single line per entry).
--setmtime
Set timestamps of all files to match their SCM-side times (the timestamp of the last checkin which modified them).

-K|--keep-merge-files
On merge conflict, retain the temporary files used for merging, named *-baseline, *-original, and *-merge.