GIT: Inspect each version of a file

filename=Makefile

for commit in $(git log --pretty=format:%H -- $filename); do

    git checkout -q $commit $filename

    version=$(     grep -P -o '(?<=^VERSION = ).*'      $filename)
    patchlevel=$(  grep -P -o '(?<=^PATCHLEVEL = ).*'   $filename)
    sublevel=$(    grep -P -o '(?<=^SUBLEVEL = ).*'     $filename)
    extraversion=$(grep -P -o '(?<=^EXTRAVERSION = ).*' $filename)
    name=$(        grep -P -o '(?<=^NAME = ).*'         $filename)

    printf "%s %d.%02d.%d%-5s %s\n" $commit $version $patchlevel $sublevel "$extraversion" "$name"
done

# reset the file to its state in the current commit
git checkout HEAD $filename