Fix the usage

tests_hammer.bash

#! /usr/bin/env bash
## tests_hammer.bash for onitu
## by lenormf
##

function log {
	echo "$@" 1>&2
}

function fatal {
	log "$@"
	exit 1
}

function main {
	test $# -lt 2 && fatal "Usage: $0 <n> <cmd>"

	local N="$1"

	shift
	local CMD="$@"

	local min_time=0
	local max_time=0
	local sum_time=0


	[[ "$N" =~ [0-9]+ ]] || fatal "${N} isn't a number"

	for i in $(seq "$N"); do
		local NOW="$SECONDS"

		echo "Test #${i}"
		eval "${CMD}"
		local ret=$?

		local spent=$((SECONDS - NOW))
		test "$min_time" -eq 0 && min_time="$spent"
		test "$max_time" -eq 0 && max_time="$spent"

		test $ret -eq 0 && {
			sum_time=$((sum_time + spent))
			test "$spent" -lt "$min_time" && min_time="$spent"
			test "$spent" -gt "$max_time" && max_time="$spent"
			continue
		} || {
			log "Test #${i} failed"
			break
		}
	done

	test $i -gt 1 && {
		log "Average time:" $((sum_time / $((i - 1))))s
		log "Extrema:" "${min_time}s" "/" "${max_time}s"
	} || {
		log "Time:" "$min_time"s
	}
}

main "$@"