badeline

#!/usr/bin/env bash

set -euo pipefail

# Usage: see below
#
# This is a successor to
# <https://github.com/radian-software/madeline>, which I wrote after I
# realized that the entire project could basically be superseded by
# two tiny shell functions. Really the issue Madeline was solving was
# two separate issues: offloading rarely-used giant files, and
# offloading rarely-used directories with too many inodes. For the
# former issue, I realized there were just not that many of them, and
# I could create a manual organization scheme on my NAS for them. For
# the latter issue, I realized that the files didn't need to
# physically *go* anywhere, they just needed to not have so many
# inodes. Thus a simple pair of shell functions that tars and untars
# the pathname you give it. One nice thing is that because this is
# uncompressed tar, you can change the contents and re-tar, and Borg
# will still mostly deduplicate. Probably.
#
# alias bp='badeline put'
# alias bg='badeline get'

usage() {
    cat <<"EOF" >&2
usage:
  badeline get ARCHIVE.bad.tar
  badeline put DIRECTORY
EOF
}

if (( "$#" == 0 )); then
    usage
    exit 1
fi

do_get() {
    if (( "$#" != 1 )) || [[ "$1" != *.bad.tar ]]; then
        usage
        exit 1
    elif [[ ! -f "$1" ]]; then
        echo >&2 "fatal: not a file: $1"
        exit 1
    fi
    target="${1%%.bad.tar}"
    if [[ -e "${target}" || -L "${target}" ]]; then
        echo >&2 "fatal: already exists: ${target}"
        exit 1
    fi
    tar -C "$(dirname "$1")" -xf "$1"
    rm "$1"
    echo >&2 "extracted $(basename "$1")"
}

do_put() {
    if (( "$#" != 1 )); then
        usage
        exit 1
    elif [[ ! -d "$1" ]]; then
        echo >&2 "fatal: no such directory: $1"
        exit 1
    fi
    (
        unset CDPATH
        cd "$1"
        target="$(basename "$PWD")"
        cd ..
        tar -cf "${target}.bad.tar" "${target}"
        rm -rf "${target}"
        echo >&2 "archived ${target}.bad.tar"
    )
}

cmd="$1"
shift

case "${cmd}" in
    get)
        do_get "$@"
        ;;
    put)
        do_put "$@"
        ;;
    *)
        usage
        exit 1
        ;;
esac