git-move.sh

#! /bin/bash
# Usage:
# ./git-move.sh path/to/file/or/dir path/to/destination/repo
echo "creating patch for path ${1}"
git log --name-only --pretty="format:" --follow  "${1}" \
 | sort -u | \
 xargs git log --pretty=email --patch-with-stat --reverse --full-index --binary -m --first-parent -- > "${2}/_patch_" \
&& echo "moving to destination repo at ${2}" \
&& cd "${2}" \
&& echo "applying patch" \
&& git am --committer-date-is-author-date < _patch_ \
&& echo "OK"

I liked the @dflock's version, but I wanted to keep the detailed history (not just merges), so I removed --first-parent and added --no-merges to the git-log invocation.