mount -o remount,rw rootfs
to return to read only enter:
mount -o remount,ro rootfs
I wanted to figure this out because a bug in TWRP v220.127.116.11 maimed my efs partition and bricklooped my phone. Even flashing the Stock Developer tar by Beans wouldn't bring it out of the brickloop. I was able to get out of the brickloop by following this
thread, but even though my phone booted up and the IMEI # was correct, my /efs folder was missing in action. This caused odd things to happen like my lock screen not functioning and the power button instantly turning the phone off instead of bringing up the power menu. I discovered this was because the phone was placed into something called "factory mode" and that to fix it you needed to edit some files in the efs folder, which were completely missing on my device. Member js0uth graciously sent me his efs folder from his Developer Note 3 and when I copied it to my phone it began to function normally again (big shout out to js0uth!). However, this folder was completely deleted once again after a reboot. So now you can see why I was looking for a way to copy these files using Terminal Emulator. I ended up making a Tasker profile with the Secure Settings plugin that automatically copies the files from my ext SD card to my system folder on boot of the device. In order to mount, copy/paste the files while retaining the correct permissions from the folder that js0uth sent me, and unmount the system I had the set up my Secure Settings command as follows:
mount -o remount,rw rootfs;cp -Rpf /storage/extSdCard/efs/* /efs/;mount -o remount,ro rootfs
So now I have a livable workaround for my problem until I can discover a way for the phone to rebuild my own /efs folder.
Edit: See radionerd's post
for a permanent fix to this issue and be sure to hit thanks under his name if it helps you.
Not sure if this will help anyone else, but I searched forever trying to figure out how to write into the system folder using Terminal Emulator on the Note 3 to no avail. I found a slew of posts that said to type "mount -o rw,remount /system" to achieve this. When I used this command it didn't return any errors so I assumed it worked, however no files ended up being copied and pasted to the location I wanted. I found numerous other examples that were supposed to enable writing to the system as well, but none of them worked. I finally figured out how to get it to work on my Note 3 by typing "mount" in terminal emulator and noticing that at the very beginning of the string that was returned was "rootfs". So if you are wanting write to your system using Terminal Emulator on the VZW Note 3 here is what ended up working for me: