Add Co-Authored-By to all commits after pairing
TL;DR
Here's the full solution:
shell
git filter-branch --msg-filter "ruby -e'puts [$stdin.read,nil,*ARGV].join(%{\\n})' -- 'Co-Authored-By: John Doe <[email protected]>'" origin/master..HEAD
Now let's break it down, piece by piece.
The commits
This will list all commits that are in your branch but not on origin/master
shell
origin/master..HEAD
The filter
The simplest ruby script that will:
- read the original commit message from
$stdin - append any provided argument with a new line
ruby
puts [
$stdin.read,
nil, # extra empty line, for good measure
*ARGV
].join(%{\n})
And we use -- to separate file names to execute from CLI arguments:
shell
$ ruby -e 'p ARGV' -- "anything after '--'" "ends up in ARGV"
["anything after '--'", "ends up in ARGV"]
Putting it all together
We're lucky git filter-branch has an option for changing commit messages, we'll use that to append Co-Authored-By: … information to every commit in the current branch.
The --msg-filter option will execute a script that will take the old message as its standard input and use the standard output as the new message.
shell
git filter-branch --msg-filter "ruby -e'puts [$stdin.read,nil,*ARGV].join(%{\\n})' -- 'Co-Authored-By: John Doe <[email protected]>'" origin/master..HEAD
