copy a couple of files to mount point dir

backup_files.sh

#!/usr/bin/env bash
# backup a couple of files into time machine backups
# main purpose it to make it easier to reinstall gentoo with similar setup
# run under mwest crontab
set -euf -o pipefail

# I don't want to leave /mnt/share mounted as it prevents hibernation of UTM
# So mount it if it is not mounted, and unmount it at the end if it wasn't mounted

declare IS_MOUNTED
declare -r MOUNT_POINT="/mnt/share"
declare -r -a BACKUP_FILES=(
  "/home/mwest/.config/modprobed.db"
  "/var/lib/portage/world"
)
declare -r BACKUP_DIR="${MOUNT_POINT}/gentoo_backup/"

# && true avoids set -e exiting the script on non-zero return code
# see https://www.gnu.org/software/bash/manual/html_node/The-Set-Builtin.html
IS_MOUNTED=$(findmnt --mountpoint "${MOUNT_POINT}") && true
echo "IS_MOUNTED is ${IS_MOUNTED}" 

# mount if not already mounted
if [[ ${IS_MOUNTED} ]];then
  echo "${MOUNT_POINT} is already mounted" 
else
  echo "mounting ${MOUNT_POINT}" 
  mount "${MOUNT_POINT}"
fi

for file in "${BACKUP_FILES[@]}"
do
  cmd="cp "
  cmd+="$file "
  cmd+="${BACKUP_DIR}"
  cmd+=$(basename "$file")
  echo "$cmd"
  $cmd
done

# umount if not initially mounted
if [[ ${IS_MOUNTED} ]];then
  echo "leaving ${MOUNT_POINT} mounted" 
else
  echo "unmounting ${MOUNT_POINT}" 
  umount "${MOUNT_POINT}"
fi