how-big

#!/usr/bin/env bash
set -euo pipefail
# Note: we still allow partial results when permission errors occur on some
# entries. We capture non-zero exits from find/du as "partial" rather than
# failing the script, but keep pipefail to catch genuine pipeline issues.

SCRIPT_NAME=$(basename "$0")

usage() {
	cat <<EOF
Usage: $SCRIPT_NAME [-a] [directory]

Displays the size of files and subdirectories in the specified directory,
sorted in descending order by size.

If no directory is provided, the current working directory is used.

Options:
  -a           Show individual file sizes in addition to directories
  -h, --help   Show this help message and exit

Examples:
  $SCRIPT_NAME ~/.local/share
  sudo $SCRIPT_NAME
  $SCRIPT_NAME .
  $SCRIPT_NAME -a /home/user
EOF
	exit 0
}

# Default behavior (show directories only)
SHOW_FILES="false"

# Parse command-line arguments
while [[ $# -gt 0 ]]; do
	case "$1" in
	-a) SHOW_FILES="true" ;; # Enable file size display
	-h | --help) usage ;;    # Show help and exit
	*) TARGET_DIR="$1" ;;    # Assume anything else is the directory argument
	esac
	shift
done

# Default to the current directory if no path is given
TARGET_DIR="${TARGET_DIR:-.}"

# Ensure the given path exists and is a directory
if [[ ! -d $TARGET_DIR ]]; then
	echo "Error: '$TARGET_DIR' is not a valid directory." >&2
	exit 1
fi

# Run the disk usage command with optional file inclusion
DU_TMP=$(mktemp)
partial=false
trap 'rm -f "$DU_TMP"' EXIT

if [[ "$SHOW_FILES" == "true" ]]; then
	# Cross-platform: use find + du for files, then du for directories
	if ! find -- "$TARGET_DIR" -maxdepth 1 -type f -exec du -h {} + >>"$DU_TMP" 2>/dev/null; then
		partial=true
	fi
	if ! du -h -d 1 -- "$TARGET_DIR" >>"$DU_TMP" 2>/dev/null; then
		partial=true
	fi
else
	if ! du -h -d 1 -- "$TARGET_DIR" >>"$DU_TMP" 2>/dev/null; then
		partial=true
	fi
fi

sort -hr "$DU_TMP" | uniq

if [[ "$partial" == true ]]; then
	echo "Warning: some entries were skipped (e.g., permission denied)." >&2
fi