rwhere.sh

rwhere() {(
	# Perform a recursive `where` (zsh only).
	#
	# Recursively resolve each alias and symbolic link until done, and do it for each potential match in PATH.

	absolute-path() {(
		# get absolute directory for an existing file without resolving symlinks
		echo "$(cd "$(dirname "$1")" && pwd)/$(basename "$1")"
	)}

	query="$1"

	if [[ ! -v RWHERE_INDENT ]]; then
		RWHERE_INDENT=""
	fi

	if [[ "$query" =~ "^/" ]]; then
		# Handle absolute paths ========================================================================================
		if link="$(readlink "$query")"; then
			# path is a symlink
			absolute_link="$link"
			if [[ ! "$link" =~ "^/" ]]; then
				absolute_link="$(absolute-path "$(dirname "$query")/$link")"
			fi

			echo "$RWHERE_INDENT$query is a link to $link"
			RWHERE_INDENT="$RWHERE_INDENT  " rwhere "$absolute_link"

		elif resolved_path="$(realpath -q "$query")"; then
			# path exists
			echo "$RWHERE_INDENT$resolved_path found"

		else
			# path does not exist
			echo "$RWHERE_INDENT$query not found"
		fi
	else
		# Handle other commands ========================================================================================
		whence -av "$query" | while read -r line ; do
			if [[ "$line" =~ "^$query is an alias for (.+)$" ]]; then
				echo "$RWHERE_INDENT$line"

				arg0=$(python3 -c "import shlex; print(shlex.split(input())[0])" <<< "$match[1]")

				if [[ "$query" != "$arg0" ]]; then
					# only recurse if the alias was not to the same command with flags
					RWHERE_INDENT="$RWHERE_INDENT  " rwhere "$arg0"
				fi

			elif [[ "$line" =~ "$query is (/.+)" ]]; then
				# When an absolute path is first reported by whence, it is now processing PATH, which we do better
				# manually because we can find broken symlinks.
				break
			else
				# Other boring cases: reserved words, etc.
				echo "$RWHERE_INDENT$line"
			fi
		done

		echo -n "$PATH" |\
			tr : "\0" |\
			xargs -I{} --null find {} -name "$query" 2>/dev/null |\
			while read -r found_path
		do
			echo "$RWHERE_INDENT$query is $found_path"
			RWHERE_INDENT="$RWHERE_INDENT  " rwhere "$found_path"
		done
	fi
)}