expr applet bug?

[Luciano Miguel Ferreira Rocha]

On Fri, Dec 08, 2006 at 08:47:34PM +0100, Cristian Ionescu-Idbohrn wrote:
> Isn't that a bug too? Does bb need to imitate bugs too?

It's the defined behaviour in the documentation:

Exit status is:
 * 0 if EXPRESSION is neither null nor 0,
 * 1 if EXPRESSION is null or 0,
 * 2 if EXPRESSION is syntactically invalid,
 * and 3 if an error occurred.

I suggest:

# check text against regex (first argument)
check() {
	regex="$1"
	shift
	result=$(./busybox expr "${*}" : "$regex")
	[ -z "$result" ] && return 1
	return 0
}

$ check '[^0-9]\+\([0-9]\+\)' xyz0 ; echo $?: $result
0: 0
$ check '[^0-9]\+\([0-9]\+\)' 0xyz0 ; echo $?: $result
1:

-- 
lfr
0/0
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