#!/bin/sh -eu
# A target must not be rebuilt when a dependency of a dependency of a dependency does not change.
>all.do printf 'redo-ifchange a\n'
>a.do printf 'redo-ifchange b\ndate +%s\n'
>b.do printf 'redo-ifchange c\ndate +%s\n'
>c.do printf 'redo-ifchange d\ndate +%s\n'
>d printf '1'
redo
d printf '1'
redo