carcass/carcass-absorb

#! /bin/bash

usage() {
    printf "Usage: %s -[dhv] DIR\n" "$0"
    printf "\nEnter DIR, grab the md5sums of all the files in there, then tar the directory up and move it to an object named after its own md5sum.\n"
    printf "\n\t-d\tDry run\n\t-h\tPrint this help\n\t-v\tRun verbosely\n"
}

inner_md5_cmd() {
    find ./ -type f -print0 | sort -z | xargs -0 md5sum
}

dryrun=0
verbose=0
while getopts dhv opt; do
    case $opt in
        d) dryrun=1 ;;
        v) verbose=1 ;;
        h) usage; exit 0 ;;
        ?) 2>&1 usage; exit 1 ;;
    esac
done
shift $(( OPTIND - 1 ))

objdir=.carcass
[[ -d $objdir ]] || {
    if [[ $verbose -eq 1 ]]; then
        mkdir -v ./$objdir
    else
        mkdir ./$objdir
    fi
}
[[ -d "$1" ]] || {
    2>&1 printf "%s is not a directory\n" "$1"
    exit 1
}

target=$(basename "$1")
if [[ $verbose -eq 1 ]]; then
    printf "Targeting '%s'\n" "$target"
    pushd "$target"
else
    pushd "$target" > /dev/null
fi
md5file=md5sums
[[ -f $md5file ]] && {
    2>&1 printf "%s already exists; refusing to clobber.\n" "$md5file"
    exit 2
}

if [[ $verbose -eq 1 ]]; then
    printf "Writing md5sums\n"
    if [[ $dryrun -eq 0 ]]; then
        inner_md5_cmd | grep -v $md5file | tee $md5file
    else
        inner_md5_cmd
    fi
else
    if [[ $dryrun -eq 0 ]]; then
        inner_md5_cmd | grep -v $md5file > $md5file
    fi
fi
popd > /dev/null

if [[ $dryrun -eq 1 ]]; then
    printf "Nothing more can be done in dry run. Exiting.\n"
    exit 0
fi
if [[ $verbose -eq 1 ]]; then
    printf "\nTarring %s\n" "$target"
    tar -cvf "$target".tar "$target"/
else
    tar -cf "$target".tar "$target"/
fi

md5=$(md5sum "$target".tar | awk '{print $1}')
if [[ $verbose -eq 1 ]]; then
    printf "'%s.tar' has md5sum %s\n" "$target" "$md5"
fi
prefix="${md5:0:2}"
suffix="${md5:2}"
mkdir -p ${objdir}/$prefix
if [[ $verbose -eq 1 ]]; then
    mv -v "$target".tar ${objdir}/${prefix}/${suffix}.tar
else
    mv "$target".tar ${objdir}/${prefix}/${suffix}.tar
fi || exit 4

if [[ $verbose -eq 1 ]]; then
    rm -rv "$target"
else
    rm -r "$target"
fi