git-split-repository

#!/bin/sh

set -ex

d="$PWD"
src=$1
shift

# expects command line options like
#	bspfiles='s,^data/(?=.*(?:\.bsp|/lm_.*\.tga)$),,' \
#	a_nonbsp=
# i.e. like filter-index, but with reponame= instead of .

repos=`for x in "$@"; do
	case "$x" in
		delete=*)
			;;
		*=*)
			echo "${x%%=*}"
			;;
	esac
done | sort -u`

export filterfile=`mktemp`

for r in $repos; do
	rsync -vaSHP --delete "$src" "$r.git/"
	cd "$r.git"
	for x in "$@"; do
		case "$x" in
			*=*)
				rr=${x%%=*}
				f=${x#*=}
				if [ x"$r" = x"$rr" ]; then
					printf -- "+%s\0" "$f"
				else
					printf -- "-%s\0" "$f"
				fi
				;;
		esac
	done >"$filterfile"
	git filter-repository "$filterfile"
	cd "$d"
done

rm -f "$filterfile"