tools/add_syntax_equal_proto2_to_all.sh

#!/usr/bin/env bash

# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You 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.

# Add 'syntax="proto2";' to the beginning of all proto files under 
# PWD(recursively) if the proto file does not have it.
for file in $(find . -name "*.proto"); do
    if grep -q 'syntax\s*=\s*"proto2";' $file; then
        echo "[already had] $file";
    else 
        sed -i '1s/^/syntax="proto2";\n/' $file
        echo "[replaced] $file"
    fi
done