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.
