code_stats.sh

#!/bin/sh
project_dir=$1
cd $project_dir

stats_for_month(){
    java_files="$(find \. -mindepth 1 -type f -name '*.java' -print)"
    kotlin_files="$(find \. -mindepth 1 -type f -name '*.kt' -print)"

    java_files_nr=$(echo "$java_files" | wc -l)
    kotlin_files_nr=$(echo "$kotlin_files" | wc -l)

    java_code_nr=$(echo "$java_files" | xargs cat | awk '/[a-zA-Z0-9]/ {i++} END{print i}')
    kotlin_code_nr=$(echo "$kotlin_files" | xargs cat | awk '/[a-zA-Z0-9]/ {i++} END{print i}')
    
    echo "Stats for: $1"
    echo "  Java: files: $java_files_nr, code lines: $java_code_nr"
    echo "  Kotlin: files: $kotlin_files_nr, code lines: $kotlin_code_nr"
}

checkout_by_month(){
    for m in 1 2 3 4 5 6 7 8 9 10 11 12; do
    date=$(echo $(date -d $m/1/1 +%b) $(date -d "$(($m%12+1))/1 - 1 days - 1 year" +%d) $(date -d "- 1 year" +%Y))
    
    git -c advice.detachedHead=false checkout `git rev-list -1 --before="$date" develop` -q
    stats_for_month "$date"
    done
}

checkout_by_month