I have to restore the /etc/passwd file I accidentally renamed in my Ubuntu Server, so I booted the machine using a LiveCD.

Problem is, the system filesystem does not appear in Nautilus, under 'Devices'. Am I missing anything?

ubuntu@ubuntu:~$ sudo fdisk -l
Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors 
Units = sectors of 1 * 512 = 512 bytes 
Sector size (logical/physical): 512 bytes / 512 bytes 
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000956dc

Device Boot         Start         End      Blocks   Id  System
/dev/sda1   *        2048      499711      248832   83  Linux
/dev/sda2          501758   625141759   312320001    5  Extended
/dev/sda5          501760   625141759   312320000   8e  Linux LVM


ubuntu@ubuntu:~$ mount
/cow on / type overlayfs (rw)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
/dev/sr0 on /cdrom type iso9660 (ro,noatime)
/dev/loop0 on /rofs type squashfs (ro,noatime)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ubuntu)

ubuntu@ubuntu:~$ sudo blkid
/dev/loop0: TYPE="squashfs" 
/dev/sda1: UUID="aad69790-198d-45bc-9ccd-e4cba7456914" TYPE="ext2" 
/dev/sda5: UUID="wbIDX7-RILL-VtFT-gX15-N1GJ-Yyfg-V8Oe5m" TYPE="LVM2_member" 
/dev/sr0: LABEL="Ubuntu 12.04 LTS i386" TYPE="iso9660"

ubuntu@ubuntu:~$ cat /etc/fstab
overlayfs / overlayfs rw 0 0
tmpfs /tmp tmpfs nosuid,nodev 0 0