shell script to find out in which git-branch the last time a file was modified

git-file-branch.sh

# usage:
#  ./git-file-branch.sh fn.cpp

prev=$(git rev-parse $(git rev-list -n1 --all -- $1)^)                                                                                                                            
for br in $(git branch -a | cut -c 3-); do                                                                                                                                           
    [ "x$(git rev-list -n1 --no-merges --first-parent $prev..$br -- $1)" != "x" ] && echo $br                                                                                     
done