acme/bin/t2s

#!/usr/bin/env bash

awk -v n_spaces="$1" '

BEGIN {
	tab = "	"
	space = " "

	if (n_spaces < 1) {
		n_spaces = 4
	}

	spaces_per_tab = ""
	for (i = 1; i <= n_spaces; i += 1) {
		spaces_per_tab = spaces_per_tab space
	}
}

function spaces_for_n_tabs(n) {
	spaces = ""
	while (n--) {
		spaces = spaces spaces_per_tab
	}
	return spaces
}

function tabs_to_spaces(line) {
	n_tabs = 0
	for (i = 1; i <= length(line); i += 1) {
		if (substr(line, i, 1) != tab) {
			break
		}
		n_tabs += 1
	}
	return spaces_for_n_tabs(n_tabs) substr(line, i)
}

{
	print tabs_to_spaces($0)
}

'