update submodules

update-submodules.sh

#!/bin/bash
for S in submodules/*; do
    echo "Updating $S"
    git -C $S checkout --quiet master
    git -C $S pull --quiet origin master
    if ! git diff --quiet $S; then
        (echo "update $(basename $S)"; echo; git submodule summary $S) | git commit -F- $S
    fi
done