Applies the contents of file(s) at the given ref (e.g. branch or commit) to the current working tree.

git-pickfile.sh

#!/usr/bin/env bash
#
# git-pickfile
#
# Applies the contents of file(s) at the given ref (e.g. branch or commit) to
# the current working tree. If there are no conflicts, the changes will be
# staged. If there are conflicts, the changes will need to be resolved and
# committed.
#
# Unlike `git checkout <ref> -- <file>`, this allows you to resolve conflicts
# instead of just discarding changes in the current tree.

REF=$1;
shift;
FILES="$*";

if [ -z "$FILES" ]; then
    echo "Usage: git-pickfile <ref> <file> [<file> ...]"
    exit 1;
fi

set -euxo pipefail
git diff $(git merge-base @ "$REF") "$REF" $FILES | git apply --3way