How to unpack rpm

I rarely use this one but it's handy sometimes:

rpm2cpio rpmname.rpm | cpio -idv

(taken from this blog)

edit:

sometimes it doesn't work because of this:

cpio: Malformed number

but it seems that cpio is broken and it can be fixed with:

rpm2cpio rpmnamerpm | lzma -d | cpio -id

(taken from another blog)