repo: add script to update all branches

update-repos.sh

+#!/bin/bash
+# Copyright (c) 2018 Pietro Albini <pietroalbini@ubuntu-it.org>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+set -euo pipefail
+IFS=$'\n\t'
+
+REPOS_DIR="repos"
+
+repos="$(ls "${REPOS_DIR}")"
+for repo in "$repos"; do
+    # Update the repo
+    git -C "${REPOS_DIR}/${repo}" fetch --all
+    git -C "${REPOS_DIR}/${repo}" reset --hard origin/master
+
+    # Commit the changes
+    git add "${REPOS_DIR}/${repo}"
+    if ! git diff --staged --exit-code --quiet; then
+        git commit -m "${REPOS_DIR}/${repo}: use latest commit"
+    fi
+done