Plot the length history of a file in a git repo

gistfile1.bash

file_length_history() {
    export filename="$1"
    (
        echo set xlabel \"Days Ago\"
        echo set ylabel \"Bytes\"
        echo plot \"-\" title \"$filename\" with lines
        now=$(date +"%s")
        git log --reverse --format=format:"%at %H" "$filename" | \
            while read -a line; do
                echo -en "$(echo scale=10\; \(${line[0]} - $now\) / 24 / 60 / 60 | bc)\t"
                git cat-file -s $(git ls-tree ${line[1]} -- "$filename" | cut -d ' ' -f 3 | cut -f 1)
            done
        unset filename
    ) | gnuplot -p
}

# Example:
#   file_length_history Current-Todo.md