Documentation says:

$ fossil help clean
Usage: fossil clean ?--force? ?--dotfiles?
...
You will be prompted before removing each file. If you are
sure you wish to remove all "extra" files you can specify the
optional --force flag and no prmpts will be issued.

However, --force doesn't work (Fossil asks before removing files). Code in checkin.c (2e4a6e1c0f) says it wants "--all" option:

  allFlag = find_option("all","a",0)!=0;

And "--all" option actually works.

So either code or documentation needs to be updated.

drh added on 2009-10-11 19:53:14:
Check-in 5308e468153

anonymous added on 2009-10-11 20:29:39:
Thanks!

Also, here's an update for www/reference.wiki, since it has the old -all option and lacked --dotfiles.

--- www/reference.wiki
+++ www/reference.wiki
@@ -214,18 +214,22 @@
     unless the "--nosign" options is used.  All files that have
     changed will be committed unless some subset of files is specified
     on the command line.
 
 <hr><a href="#tof">&#710;</a>
-    <a name="clean">Usage: </a><a href="cmd_clean.wiki">fossil clean</a> ?-all?
+    <a name="clean">Usage: </a><a href="cmd_clean.wiki">fossil clean</a> ?--force? ?--dotfiles?
     Delete all "extra" files in the source tree.  "Extra" files are
     files that are not officially part of the checkout.  See also
     the "extra" command. This operation cannot be undone.
 
     You will be prompted before removing each file. If you are
     sure you wish to remove all "extra" files you can specify the
-    optional -all flag.
+    optional --force flag and no prmpts will be issued.
+
+    Files and subdirectories whose names begin with "." are
+    normally ignored.  They are included if the "--dotfiles" option
+    is used.
 
 <hr><a href="#tof">&#710;</a>
     <a name="clone">Usage: </a><a href="cmd_clone.wiki">fossil clone</a> URL FILENAME
     Make a clone of a repository specified by URL in the local
     file named FILENAME.