testsuite/hostid/hostid-works - nest-cam/v179/busybox - Git at Google

 h=x$(busybox hostid)
 # Is $h a sequence of hex numbers?
 x="${h//[0123456789abcdef]/x}"
 x="${x//xxx/x}"
 x="${x//xxx/x}"
 x="${x//xxx/x}"
 x="${x//xx/x}"
 test x"$x" = x"x"
	h=x$(busybox hostid)
	# Is $h a sequence of hex numbers?
	x="${h//[0123456789abcdef]/x}"
	x="${x//xxx/x}"
	x="${x//xxx/x}"
	x="${x//xxx/x}"
	x="${x//xx/x}"
	test x"$x" = x"x"