The swapoff applet seems to be broken in BusyBox 1.19.0. I suppose this is caused by some change in libbb/getopt32.c, since this is the place where the error is coming from. Steps to reproduce: 1) download & extract BusyBox 1.19.0 source 2) make defconfig && make 3) ./busybox swapoff Outcome: [root@i7-820qm busybox-1.19.0]# ./busybox swapoff swapoff: NO OPT p! Additional information: The same happens when arguments are passed to swapoff [root@i7-820qm busybox-1.19.0]# ./busybox swapoff -a swapoff: NO OPT p! [root@i7-820qm busybox-1.19.0]# ./busybox swapoff /dev/sda4 swapoff: NO OPT p! This problem occurs on both my laptop (output above) and an ARM device (Nokia N900). P.s. there's no "1.19.x" in the "Version" listbox of BusyBox' bugtracker yet, so I'll set the version to "unspecified".
Just noticed there's already a hotfix for this (http://busybox.net/downloads/fixes-1.19.0/busybox-1.19.0-swap.patch). I'm sorry for the bugtracker noise. Closing this bug as resolved.