The "update" command:

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

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

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 check-out are subject to being updated and the version of the current check-out is changed to VERSION. Any uncommitted changes are retained and applied to the new check-out.

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 check-out or the repository.

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

Options:

--case-sensitive BOOL
Override case-sensitive setting
--debug
Print debug information on stdout
-n|--dry-run
If given, display instead of run actions
--force-missing
Force update if missing content after sync
-K|--keep-merge-files
On merge conflict, retain the temporary files used for merging, named *-baseline, *-original, and *-merge.
--latest
Acceptable in place of VERSION, update to latest version
--nosync
Do not auto-sync prior to update
--proxy PROXY
Use PROXY as http proxy during sync operation
--setmtime
Set timestamps of all files to match their SCM-side times (the timestamp of the last check-in which modified them).
-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).