In emergency mode, you are booted into the most minimal environment
possible. The root file system is mounted read-only and almost
nothing is set up. The main advantage of emergency mode over
single-user mode is that the init files are not
loaded. If init is corrupted or not working, you can
still mount file systems to recover data that could be lost during a
re-installation.
To boot into emergency mode, use the same method as described for
single-user mode in Section 5.3 Booting into Single-User Mode with
one exception, replace the keyword single
with the keyword emergency.
