In bash:
for CONTRIBUTOR in $(git log --format='%ae' | sort -u); do
echo "${CONTRIBUTOR}";git log --shortstat --author="${CONTRIBUTOR}" | \
grep -E "fil(e|es) changed" | \
awk '{files+=$1; inserted+=$4; deleted+=$6} END {print "files changed: ", files, "lines inserted: ", inserted, "lines deleted: ", deleted }'
done