estimate space actually used by snapshots of a dataset

zfs-reclaim.bash

#!/usr/bin/env bash
# vim:set et sw=2 ts=2:
# estimate space actually used by snapshots of a dataset
# original by https://www.reddit.com/r/zfs/comments/bzo817/running_out_of_space_easy_way_to_visualize/er0ccbe/
# edits by me
# NO WARRANTY

set -euxo pipefail

here="$(realpath "$1")"

{ echo -e "NAME\tRECLAIM";
for snapshot in $(zfs list -Hpr "$here" -t snapshot -o name -s creation -d 1); do
  echo -ne "$snapshot\t"
  zfs destroy -nv "${snapshot/@/@%}" | sed -nre "s/would reclaim (.+)/\1/p"
done } | column -t