[cc lang='bash']
# backup
\$ dd if=/dev/mmcblk0 | gzip > raspi.img.gz

# restore backup
\$ gunzip -c raspi.img.gz | dd of=/dev/mmcblk0
[/cc]

INFO: /boot is formatted vfat, / is formatted f2fs (in case you need to change something before restoring to card)
[cc lang='bash']
pi@raspbmc:\~\$ cat /etc/fstab
proc /proc proc defaults 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620 0 0
/dev/mmcblk0p1 /boot vfat defaults,noatime 0 0
/dev/mmcblk0p2 / f2fs defaults,noatime 0 0
[/cc]