Most of the experienced users on this site don't use NOOBS - even on the Foundation Forum experienced users tell new users not to use it - I don't know why the Foundation keeps recommending it.
Unless you have something worth recovering I suggest you use Etcher to install Raspbian to a SD Card (like the vast bulk of us).
If you get to a recovery console it MAY work if you use
sudo fsck.ext4 -y /dev/mmcblk0p6 (as in the tutorial).
NOTE that tutorial is obsolete, I doubt NOOBS has a root password, and if logged as root you don't need
PS Most of us don't attempt recovery - we just restore from a backup if the image becomes corrupt.
PPS If you do a fresh Raspbian install, use a new SD Card, and you may be able to mount the old SD Card and recover files.
The following is the normal recovery process (assuming you can find
cmdline.txt - which WON'T be on the 1st partition - probably p5)
init=/bin/sh at the end of
cmdline.txt and reboot.
- After booting you will be at the prompt in a root shell.
- Your root file system is mounted as readonly now, so remount it as read/write
mount -n -o remount,rw /
Just to be clear the above will NOT allow FS repair (this needs a different working root partition) but allows access to files and sometimes lets problems be corrected manually.