git diff all local branches for a line in a file

gistfile1.txt

#searches all local branches 
git branch | cut -d" " -f 3 | grep -Ev "^$" | while read line; do git diff $line <replace_with_file_path>; done | grep <replace_with_search_string>

#example:
#search diffs in all branches in the packages.json file (at the root of current directory) for the term "debug"
git branch | cut -d" " -f 3 | grep -Ev "^$" | while read line; do git diff $line package.json; done | grep debug