Find all initial commits and the commits where they were merged

git-find-roots

#!/bin/bash
#
# git-find-roots finds every commit with no parent (initial commits)
# and the commit where they were merged.
#
# Usage:
#   git-find-roots [commit-ish]
#
# Example:
#   git-find-roots master
#

BRANCH=${1:-master}

find_roots() {
	branch=$1
	git rev-list --max-parents=0 $branch
}

find_merge() {
	commit=$1
	branch=$2
	perl -ne 'print if ($seen{$_} .= @ARGV) =~ /10$/' <(git rev-list --ancestry-path $commit..$branch) <(git rev-list --first-parent $commit..$branch) | tail -n 1
}


for root in $(find_roots $BRANCH) ; do
	merge=$(find_merge $root $BRANCH)
	echo "root $root was merged in $merge"
done

To clarify, it finds all root commits of the specified branch, which is not necessarily ALL root commits in the repository.