The "blame" command:

Usage: fossil annotate|blame|praise ?OPTIONS? FILENAME

Output the text of a file with markings to show when each line of the file was last modified. The version currently checked out is shown by default. Other versions may be specified using the -r option. The "annotate" command shows line numbers and omits the username. The "blame" and "praise" commands show the user who made each check-in.

Reverse Annotations: Normally, these commands look at versions of FILENAME moving backwards in time back toward the root check-in, and thus the output shows the most recent change to each line. However, if the -o|--origin option is used to specify some future check-in (example: "-o trunk") then these commands show changes moving towards that alternative origin. Thus using "-o trunk" on an historical version of the file shows the first time each line in the file was changed or removed by any subsequent check-in.

Options:

--filevers
Show file version numbers rather than check-in versions
-r|--revision VERSION
The specific check-in containing the file
-l|--log
List all versions analyzed
-n|--limit LIMIT
LIMIT can be one of:

N
Up to N versions
Xs
As much as possible in X seconds
none
No limit
-o|--origin VERSION
The origin check-in. By default this is the root of the repository. Set to "trunk" or similar for a reverse annotation.
-w|--ignore-all-space
Ignore white space when comparing lines
-Z|--ignore-trailing-space
Ignore whitespace at line end