Getting mount's usage suggestion when attempting /system remount I'm trying to remount system on a rooted Samsung GT-S6102 running Android 2.3.6:

# mount -o rw,remount,rw /system

Usage: mount [-r] [-w] [-o options] [-t type] device directory

This is exactly like in this other answer, so I'm not sure why I'm getting this usage error.
So apparently the problem was that I needed to specify the target as per the answer to this other question:

mount -o remount,rw /system /system