sort_gitmodules.sh

#!/usr/bin/env bash

# ref: https://gist.github.com/jaytaylor/fad7bc69e5f12fc2331e2c6330bd8419#gistcomment-3413386

awk 'BEGIN { I=0 ; J=0 ; K="" } ; /^\[submodule/{ N+=1 ; J=1 ; K=$2 ; gsub(/("vendor\/|["\]])/, "", K) } ; { print K, N, J, $0 } ; { J+=1 }' .gitmodules \
  | sort \
  | awk '{ $1="" ; $2="" ; $3="" ; print }' \
  | sed 's/^ *//g' \
  | awk '/^\[/{ print ; next } { print "\t" $0 }' \
  | sponge .gitmodules