Dan Kennedy has contributed a bash script that manipulates the bash prompt to show the status of the Fossil repository that the user is currently visiting. The prompt shows the branch, version, and time stamp for the current checkout, and the prompt changes colors from blue to red when there are uncommitted changes.
To try out this script, simply download it from the link above, then type:
For a permanent installation, you can graft the code into your .bashrc file in your home directory.
The code is very simple (only 32 non-comment lines, as of this writing) and hence easy to customized.