Backup script that uses rclone and ZFS snapshots to create incremental backups

rclone-backup.sh

#!/usr/bin/env bash

## Configs ##
ZFSSNAPSHOTNAME="rclone"
RCLONECONFIGPATH="/root/.config/rclone/rclone.conf"
BWLIMIT="10M"
TRANSFERS=10


mountSnapshots () {
  mkdir -p "/mnt/$RUNNAME"

  mount -t zfs "$ZFSSNAPSHOTBASE@$ZFSSNAPSHOTNAME" "/mnt/$RUNNAME"

  while read -r line
  do
    MOUNTPATH=$(echo "$line" | sed "s/$ESCAPEDZFSSNAPSHOTBASE\///" | sed "s/@$ZFSSNAPSHOTNAME//")
    if [ -d "/mnt/$RUNNAME/$MOUNTPATH" ]; then
      mount -t zfs "$line" "/mnt/$RUNNAME/$MOUNTPATH"
    fi
  done < <(zfs list -t snapshot | grep "$ZFSSNAPSHOTNAME" | grep "$ZFSSNAPSHOTBASE" | grep -v "$ZFSSNAPSHOTBASE/\." | grep -o "$ZFSSNAPSHOTBASE/[0-9,a-z,A-Z,/,[:space:]]*@$ZFSSNAPSHOTNAME" | sed 's/[[:space:]]*$//')

}

unmountSnapshots () {
  while read -r line
  do
    MOUNTPATH=$(echo "$line" | sed "s/$ESCAPEDZFSSNAPSHOTBASE\///" | sed "s/@$ZFSSNAPSHOTNAME//")
    if [ -d "/mnt/$RUNNAME/$MOUNTPATH" ]; then
      umount "/mnt/$RUNNAME/$MOUNTPATH"
    fi
  done < <(zfs list -t snapshot | grep "$ZFSSNAPSHOTNAME" | grep "$ZFSSNAPSHOTBASE" | grep -v "$ZFSSNAPSHOTBASE/\." | grep -o "$ZFSSNAPSHOTBASE/[0-9,a-z,A-Z,/,[:space:]]*@$ZFSSNAPSHOTNAME" | sed 's/[[:space:]]*$//' | tac)

  umount "/mnt/$RUNNAME"

  rmdir "/mnt/$RUNNAME"
}

cleanup () {
  cd "/"
  unmountSnapshots

  zfs destroy -r "$ZFSSNAPSHOTBASE@$ZFSSNAPSHOTNAME"

  if [ -f "/var/log/$RUNNAME.log" ]; then
    bzip2 "/var/log/$RUNNAME.log"
  fi
  rm $PIDFILE
}


trapCleanup () {
  trap SIGINT

  cleanup

  exit

}

createPIDFile () {
  if [ -f $PIDFILE ]
  then
    PID=$(cat $PIDFILE)
    ps -p $PID > /dev/null 2>&1
    if [ $? -eq 0 ]
    then
      echo "Process already running"
      exit 1
    else
      ## Process not found assume not running
      echo $$ > $PIDFILE
      if [ $? -ne 0 ]
      then
        echo "Could not create PID file"
        exit 1
      fi
    fi
  else
    echo $$ > $PIDFILE
    if [ $? -ne 0 ]
    then
      echo "Could not create PID file"
      exit 1
    fi
  fi
}

if [ $# -eq 2 ]
  then
    BASENAME=$(basename $1)
    RUNNAME="$ZFSSNAPSHOTNAME-$BASENAME"
    ZFSSNAPSHOTBASE=$(zfs list | grep "$BASENAME" | grep -v "$BASENAME/" | awk '{print $1}')
    ESCAPEDZFSSNAPSHOTBASE=$(echo "$ZFSSNAPSHOTBASE" | sed 's/\//\\\//')
    PIDFILE=/var/lock/$RUNNAME.pid
    ISOTIME=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
    YEAR=$(date -u +"%Y")

    createPIDFile

    zfs snapshot -r "$ZFSSNAPSHOTBASE@$ZFSSNAPSHOTNAME"

    trap "trapCleanup" INT

    if [ -f "/var/log/$RUNNAME.log.bz2" ]; then
      bunzip2 "/var/log/$RUNNAME.log.bz2"
    fi

    mountSnapshots

    # Do tha backup dance!
    if [[ $BWLIMIT ]]; then
      rclone --config "$RCLONECONFIGPATH" sync "/mnt/$RUNNAME" "$2:$BASENAME/current" --backup-dir "$2:$BASENAME/$YEAR/$ISOTIME" --transfers $TRANSFERS --log-file /var/log/$RUNNAME.log --log-level INFO --bwlimit $BWLIMIT
    else
      rclone --config "$RCLONECONFIGPATH" sync "/mnt/$RUNNAME" "$2:$BASENAME/current" --backup-dir "$2:$BASENAME/$YEAR/$ISOTIME" --transfers $TRANSFERS --log-file /var/log/$RUNNAME.log --log-level INFO
    fi

    # Create filelist
    # | sed 's/\[/\\\[/g' | sed 's/\]/\\\]/g' | sed 's/\?/\\\?/g' | sed 's/\*/\\\*/g' | sed 's/{/\\{/g' | sed 's/}/\\}/g'
    cd "/mnt/$RUNNAME"
    find . | sed 's/^.\/*\(.*\)/\1/' | sed '/^[[:space:]]*$/d' | bzip2 > "/tmp/filelist-$RUNNAME.bz2"
    rclone --config "$RCLONECONFIGPATH" copyto "/tmp/filelist-$RUNNAME.bz2" "$2:$BASENAME/$YEAR/$ISOTIME/filelist.bz2"
    rm "/tmp/filelist-$RUNNAME.bz2"

    cleanup
else
  echo "Argument should be: path remote"
fi

Hi, I'm a noob at this, could you add some destructions, or elaborate on the comments in the script to talk one through it please?