There are times when you mess up something on the system and you need to rescue it using safe boot etc. However, this can be a real daunting task if you need a fast cure to most common problems. Like for example if you have stuff where you need to remount and extend partitions etc.
Solution: Boot using Live-CD!
1. Boot to your Live-CD environment
2. Create a virtual directory to mount the partition
3. Issue the command: #mount -t fs.type -o "options" /path/partion /path/directory
4. Issue the command #chroot /path/directory
This drops you to the working directory of your current system and fix things. Note, that you may have to mount all partitions to the same directory to get all the libraries needed to run the system correctly.