little-things/format-size

#!/bin/bash
# Format size in bytes into a readable string of the form "1.23 KiB"; reads from stdin and arguments and can take multiple numbers separated by any amount of whitespace including newlines
{
	if [ ! -t 0 ]; then cat; fi
	echo "$@"
} |
	tr '\t ' '\n' |
	awk '
		BEGIN {
			units[0] = "B";
			units[1] = "KiB";
			units[2] = "MiB";
			units[3] = "GiB";
			units[4] = "TiB";
			units[5] = "PiB";
		}

		{
			size += $1;
		}

		END {
			if (size > 0) {
				magnitude = int(log(size) / log(1024));
				if (magnitude > 5) {
					magnitude = 5;
				}
			} else {
				magnitude = 0;
			}
			if (magnitude > 0) {
				sizeformat = "%.2f";
			} else {
				sizeformat = "%d";
			}
			printf sizeformat " %s\n", size / (1024 ^ magnitude), units[magnitude];
		}'