Script to backup (compress and pgp encrypt) a file or directory and send it anywhere via ssh.

backup-tool.sh

#!/bin/bash

# Usage: script <source file/directory> <gpg recipient> <ssh login@server>:<target directory> [chmod]
# Example: /usr/local/bin/backup-tool.sh /home/alice/bwdata [email protected] [email protected]:backups/ 0600
# Example crontab: 0 5 * * * <see example above>
# Notes: Remember that elevated permissions is required to read some dirs/files
#        Remember to add and trust the GPG recipient, otherwise the encryption will fail

[ -z "$1" ] && echo "No source file/directory" && exit 1
[ -z "$2" ] && echo "No recipient" && exit 1
[ -z "$3" ] && echo "No backup server" && exit 1

gpg --list-keys "$2" || (echo "Recipient not in keyring" && exit 1)

root="/tmp"

mkdir -p "$root"
fn="$root/$(basename "$1")-$(date +"%Y%m%d-%H%M%S").tar.zip"

echo "Creating tarball"
cd "$(dirname "$1")" && tar czfP "$fn" "$(basename "$1")"

echo "Encrypting tarball to recipient $2"
gpg --encrypt --recipient "$2" --trust-model always --output "$fn.pgp" "$fn"

echo "Deleting tarball"
rm -f "$fn"

if [ -n "$4" ]; then
        echo "Updating encrypted backup permissions"
        chmod "$4" "$fn.pgp"
fi

echo "Sending encrypted backup to $3"
scp "$fn.pgp" "$3"

echo "Cleanup"
rm -f "$fn.pgp"

echo "Done"

last-backups.sh

#!/bin/bash

# Outputs or writes to file a JSON snippet of the last time files were backed
# up (created by backup-tool.sh; .pgp) in the specified users' home directories.
# Usage: last-backups [output file]

USERS=(backups-vaultwarden backups-gitea backups-mystats backups-media)

lastForDir() {
        # Alternative datetime format: '%TY-%Tm-%Td %TT', tho sort has to be used differently in that case
        datetime="$(find "/home/$1" -name '*.pgp' -type f -printf '%T@\n' | sort -nr | grep -m  1 '')"
        echo $'\t'"\"$1\": $datetime,"
}

for user in ${USERS[@]}; do
        output+="$(lastForDir $user)\n"
done

# Remove last comma
output="${output::-3}\n"

# Print to stdout if no output file was provided
if [ -z "$1" ]; then
        echo -e "{\n$output}"
        exit 0
fi

# Write to file if not exists
if [ ! -f "$1" ]; then
        echo -e "{\n$output}" > "$1"
        exit 0
fi

# Calc md5 for old file and new output
old=$(md5sum "$1" | cut -d' ' -f1)
new=$(echo -e "{\n$output}" | md5sum | cut -d' ' -f1)

# Compare md5 to only write to output if updated
if [[ "$old" != "$new" ]]; then
        echo -e "{\n$output}" > "$1"
fi

Added last-backups.sh—a script to help verifying that backups works as intended. I use it to keep a .json file in my home dir on my backup server with the last update times and poll that file on my main computer system start/daily (ssh <server> "cat last-backups.json") to alert me if backups have not been made on time.