Simple backup to an external volume with `bup`

backup

#!/bin/bash

set -e

VOLUME=Tigh

function die {
    echo "`basename -- "$0"`:" "$@" 1>&2
    exit 1
}

if [[ ! -d "/Volumes/$VOLUME" ]]; then
    die "volume \`$VOLUME' not mounted"
fi

if ! command -v "bup" &>/dev/null; then
    die "command \`bup' not found"
fi

export BUP_DIR="/Volumes/$VOLUME/.bup"
bup index -u "$HOME"
bup save -n "`id -un`" "$HOME"

restore

#!/bin/bash

set -e

export BUP_DIR="/Volumes/Tigh/.bup"
export GIT_DIR="$BUP_DIR"

for file; do
	bupf="`realpath "$file"`.bup"
	egrep -q "^$HOME" <<<"$bupf"
	sha1="$(git ls-tree `id -un` -- "${bupf#/}" | cut -c13-52)"
	bup join "$sha1" > "$bupf"
done