Have a look at
mount | grep mmcblk0p2, e.g., from a typical (non-NOOBS) pi:
/dev/mmcblk0p2 on / type ext4 (rw,noatime,data=ordered)
/dev/mmcblk0p1 on /boot/rpi type vfat (rw,relatime,...)
Anything that's actually mounted you should probably keep; the other partitions you can do what you want with. You can get a list with
ls -1 /dev | grep mmcblk0p. Anything in the second list not in the first list is not in use. Note the first line above, with
on /. That partition is your root filesystem.
Now, back up
/boot/cmdline.txt in case what I am recommending here doesn't work, I do not have a NOOBS card to try it on.1 Edit
cmdline.txt and find
root=/dev/mmcblk0p?? and change whatever
?? is to whatever your root filesystem partition is (in the example above,
2). It might be so already.
If everything now boots okay, you can reformat stuff in those unused partitions. You can get the sizes with
sudo fdisk /dev/mmcblk0, then
p to see the partition table. You can also delete and replace adjacent partitions to make a larger partition with fdisk, but that is another question (I'm sure you'll find stuff online about this).
When you have a partition you want to use,
sudo mkfs.ext4 /dev/mmcblk0p?? where
?? is the number. Remember, do not do this to something that was shown in
If you want to transfer, e.g., your home directories there, make sure the users are logged out (i.e., log in as
mount /dev/mmcblk0p?? /mount/extra
There should be no errors. Check in
/mnt/extra. It should contain one directory,
cp -a /home/* /mnt/extra
/mnt/extra should now be identical. There should not be a
/mnt/extra/home -- that means you left the
When you are sure this is all good, you can delete everything in
/home, but keep it as a directory:
rm -rf /home/*. This will free that space up in your root partition.
Add a line to
/dev/mmcblk0p?? /home ext4 defaults,noatime 0 3
This will mount that new partition on
/home at boot so everything is normal. You can try that now:
mount /dev/mmcblk0p?? /home
Remember, don't really use
?? anywhere. You should be able to log in as
pi or whoever and find your normal home directory.
1. In fact, I strongly recommend you back the whole card up before you try this, just in case.