Mount root filesystem as R/W I use NOTE4 N910C with Android 6.0.1 PDA N910CXXU2DPE6, CSC N910COXA2DPE1 + TWRP + root, dated Wed, 11 May 2016.
All works perfectly but in this version of firmware, root filesystem is mounted as read-only. Developer mode is turn on. 
I try to remount /system from console, from ES Explorer, from Root Explorer and so on. Nothing helps. Can anybody advice me how to make root filesys as R/W. Just for a while, to make some changes.
Finally I remount /system as R/W. The proper syntax of command is:

mount -o rw,remount /system


NOT:

mount -o remount,rw /system


I really dont know why, but second syntax is executed without errors but /system is still read only. The first command works on NOTE 4 N910C correctly.
Thats all, topic closed.