Add a tool do dump requirements and constraints for all branches

Often it's helpful to quickly compare the requirements and constraints
for a given library on all branches.  This tool does that.

Change-Id: I2458c5929d8812cd74f657050eea5f4f3fa11df0

tools/grep-all.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+# This script, when run from the root directory of this repository, will
+# search the default and feature branches of all projects listed in the
+# projects.txt file for declared dependencies, then output a list of any
+# entries in the global-requirements.txt file which are not actual
+# dependencies of those projects. Old dependencies which were removed
+# from projects or which were used only for projects which have since
+# been removed should be cleaned up, but many entries likely represent
+# recent additions which still have pending changes to add them to one
+# or more projects. In most cases, git pickaxe will yield the answer.
+
+# Note(tonyb): Expand HEAD into something that's hopefully more human
+#              readable
+declare -a branches=($(git describe --always) origin/master
+                     origin/stable/newton
+                     origin/stable/mitaka
+                     origin/stable/liberty
+                    )
+
+function search() {
+    git grep -Ei "^${1}" ${2} -- "${3}" | cut -d: -f4-
+}
+
+printf '\nRequirements\n'
+for branch in ${branches[@]} ; do
+    printf "%-22s: %s\n" $branch "$(search $1 $branch global-requirements.txt)"
+done
+
+printf '\nConstraints\n'
+for branch in ${branches[@]} ; do
+    printf "%-22s: %s\n" $branch "$(search $1 $branch upper-constraints.txt)"
+done