https://askubuntu.com/questions/963021/how-to-take-whole-ubuntu-16-04-system-backup-into-external-hard-disk

backup.sh

#!/bin/bash

# NAME: full-backup
# PATH: $HOME/bin
# DESC: Full system backup - must call with SUDO

# DATE: July 16, 2017. Modified July 26, 2017.

apt autoclean   # reduces size of /var/cache/apt/archives

cd /tmp     # tar must be created in directory not backed up.

time tar -cvpzf backup.tar.gz \
--exclude=/backup.tar.gz \
--exclude=/proc \
--exclude=/tmp \
--exclude=/mnt \
--exclude=/dev \
--exclude=/sys \
--exclude=/media \
--exclude=/usr/src/linux-headers* \
--exclude=/home/rick/.cache \
--exclude=/var/log \
--exclude=/var/run/ \
--exclude=/run \
--exclude=/var/cache/apt/archives /