Backup script

#!/bin/bash
function exiterr(){ notify-send -t 8640000 'Backup Script Failed' "${1}"; exit 1; }
function localsum(){ sha512sum "${1}" | grep -oe '[0-9a-f]\{128\}' || exiterr "Unable to get sha512sum for local file ${1##*/}"; }
function remotesum(){ $sshcmd "sha512sum ${remotebkp}${1}" | grep -oe '[0-9a-f]\{128\}' || exiterr "Unable to get sha512sum for remote file ${1}"; }

export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
export DISPLAY=:0

failssh=0
server='user@server'
gpgrecipient='user@email'
remotebkp='/path/to/remote/dir/'
localbkp='/path/to/local/dir/'
sshcmd="ssh -o BatchMode=yes -o ConnectionAttempts=3 -o ConnectTimeout=2 ${server}"

until $sshcmd 'true' >&/dev/null; do
    ((++failssh >= 30)) && exiterr "Cannot establish SSH connection to ${server}"
    sleep 1
done

uploaded=()
declare -A bkpfiles=(
    ["${HOME}/folder1.tar.gz.gpg"]="${HOME}/folder1"
    ["${HOME}/folder2.tar.gz.gpg"]="${HOME}/folder2"
    ["${HOME}/Documents/password-db.kdbx"]=''
)

for bfile in "${!bkpfiles[@]}"; do
    dirnewer=false
    bkpdir="${bkpfiles[$bfile]}"

    if [[ -d "${bkpdir}" ]]; then
        for f in "${bkpdir}"/*; do
            [[ "$f" -nt "${HOME}/${bkpdir##*/}-last-modified" ]] && dirnewer=true
        done

        if $dirnewer; then
            tarf="${bfile%.gpg}"
            tar Pczf "${tarf}" "${bkpdir}" || exiterr "Error archiving ${tarf}"
            gpg --batch --yes --output "${bfile}" --encrypt --recipient "${gpgrecipient}" "${tarf}" || exiterr "Error encrypting ${tarf}"
            rm -f "${tarf}"
            touch "${HOME}/${bkpdir##*/}-last-modified"
        fi
    fi

    lsha512="$(localsum "${bfile}")"
    rsha512="$(remotesum "${bfile##*/}")"

    if [[ "${lsha512}" != "${rsha512}" ]]; then
        lsize="$(stat -c%s "${bfile}")"
        rsize="$($sshcmd "stat -c%s ${remotebkp}${bfile##*/}")"
        ((lsize < rsize)) && exiterr "Local ${bfile##*/} filesize smaller (manual backup required)"

        scp -l 8000 -o BatchMode=yes "${bfile}" "${server}:${remotebkp}" || exiterr "Error copying ${bfile##*/} to ${server}"
        [[ -d "${localbkp}" ]] && cp "${bfile}" "${localbkp}"

        uploaded+=("${bfile##*/}")
    fi
done

if [[ -z "${uploaded[*]}" ]]; then
    notify-send -t 8640000 'Backup Script Successful' 'No uploads were needed'
else
    IFS=$'\n'
    notify-send -t 8640000 'Backup Script Successful' "Successfully uploaded files:\\n${uploaded[*]}"
fi