My filesystem is mounted read-only. How do I mount it read/write?
Use mount -u /. More than likely, you booted single-user which mounts the Root filesystem read-only by default. This gives you a chance to run fsck by hand before bringing the system up into multi-user. One other way to mount all the filesystems in /etc/fstab as read/write is to use mount -a. However, the best way to do this is to go into multi-user mode by exiting from your single-user shell. This will mount all of the filesystems in /etc/fstab in whatever mode they are listed.
