ducks: Summarize disk space usage into a local file called .ducks. Works on MacOS, FreeBSD & Linux (GNU Tools)

ducks.sh

#!/usr/bin/env bash

# Find the disk hog
# Borrowed from http://oreilly.com/pub/h/15

#set -x
set -euo pipefail

# Summarize disk space usage into a local file called .ducks

# du options
# -x      File system mount points are not traversed.
# .[^.]*  Include dotfiles, exclude '.' & '..'. Note that '--exclude' is not supported on a Mac
# $*      Allow extra grep options, like '-n'
# 2>/dev/null -- To avoid dumb errors with stuff that doesn't matter like /proc (Linux) or $USER/Library (MacOS)
# Sort options
# --human-numeric-sort: compare human readable #s (2K 1G). Doesn't work on all OSes.
# MacOS finally supports -h (human-readable) so no need for GNU & non-GNU versions

# nullglob: expand unmatched patterns to nothing instead of literal text
# dotglob: make * pattern include dotfiles (files starting with .)
shopt -s nullglob dotglob

# Build array of files to check (dotfiles and regular files)
files=(.[^.]* *)

du -chs -x $* "${files[@]}" 2>/dev/null | sort -h > .ducks ; tail .ducks

# NonGNU fallback (if sort -h not supported on FreeBSD/macOS)
#du -cks -x $* "${files[@]}" 2>/dev/null | sort -n > .ducks ; tail .ducks