One hack that can be used is (This will only work for the recent modification) you can check the last modified time for the file, and cross check with the log-in times of the users. You might be able to narrow the list down.
This will only work for the recent modification.
- use
stat
command (ex: stat <file_name>, See this) - Find the
Modify
time - Use
last
command to see the log in history (see this) - Compare the log-in/log-out times with the file's
Modify
timestamp
This will not work all the time, but you can narrow the results down.