git add Signed-off-by line using format.signoff not working
config, format, git
Solution
Update for Git 2.14.x/2.15: as I mentioned in "Git - Detect if commit is signed off programmatically", you will be able to parse a commit message trailer for `Signed-off-By` line.
"`git interpret-trailers`" has been taught a "`--parse`" and a few other options to make it easier for scripts to grab existing trailer lines from a commit log message.
See stefanct's answer for `commit-msg` client-side hook which would use `git interpret-trailers`.
Original answer (2013)
`format.signoff` is about patch (as illustrated, for instance, in this patch):
format.signoff
A boolean value which lets you enable the -s/--signoff option of `format-patch` by default
It has no bearing on `git commit -s`.
In other words, you don't have to signoff every commit, but when you are publishing them as patch for others to use (as in "git: submitting patches"), then you should sign them.
For the exact signification of `Signed-of-by`, see "What is the Sign Off feature in Git for?".
Problem
My client git version is 1.7.0.4. I want to automatically add a "Signed-off-by" line for the committer at the end of the commit log message when commit a message. - When I set `git config --global format.signoff true`, and run `git commit -m "modify something"`, I see no "Signed-off-by" in `git log`. - If I use `git commit -m -s "modify something"`, then "Signed-off-by" does show in `git log`. Can anyone help?