Add flow annotation to all files in src directory

add-flow.sh

#!/bin/bash
# Based on http://stackoverflow.com/questions/151677/tool-for-adding-license-headers-to-source-files

for i in $(find -L src -type f -name '*.js')
do
    if ! grep -q @flow $i
    then
        (echo "// @flow") > flowificator
        cat flowificator $i >$i.new && mv $i.new $i
        rm flowificator
    fi
done