Smartmontools
# info
smartctl -i /dev/sda
# healthtest
smartctl -H /dev/sda
# show attributes
smartctl -a /dev/sda
# short test
smartctl -t short /dev/sda
smartctl -l selftest /dev/sda
# long test
smartctl -t long /dev/sda
smartctl -l selftest /dev/sda
# offline test
smartctl -t offline /dev/sda
smartctl -l selftest /dev/sda
ddrescue
cd /path/to/usb-hdd
# rescue
#fdisk -l /dev/sda > fdisk-l.txt
#fdisk -lu /dev/sda > fdsik-lu.txt
# or if GPT (EFI)
parted -ls /dev/sda > parted-ls.txt
parted -lms /dev/sda > parted-lms.txt
parted /dev/sda print > parted-print.txt
ddrescue -n /dev/sda hddimage.img hddimage.log
ddrescue -d -r3 /dev/sda hddimage.img hddimage.log
# restore
dd if=hddimage.img of=/dev/sdb bs=1m
fdisk /dev/sdb
fsck.ext3
e2fsck -v -f -p /dev/sdb1
working with image
cd /path/to/usb-hd
# (paranoia :-) copy of image)
cp hddimage.img hddimage-copy.img
chmod 400 hddimage-copy.img
kpartx -av hddimage-copy.img
mkdir /mnt/p1
mount -o loop,ro /dev/mapper/loop0p1 /mnt/p1
# do what you want with the data
ls -la /mnt/p1
umount /mnt/p1
kpartx -d hdimage-copy.img
chroot into system
sudo mkdir -p /mnt/debian
sudo mount /dev/mapper/lvm--vg-root--lv--debian /mnt/debian/
sudo mount /dev/mapper/lvm--vg-var--lv--debian /mnt/debian/var/
sudo mount /dev/sda2 /mnt/debian/boot/efi/
sudo mount -o bind /dev/ /mnt/debian/dev/
sudo mount -o bind /sys/ /mnt/debian/sys/
sudo mount -o bind /proc/ /mnt/debian/proc/
#sudo cp /proc/mounts /mnt/debian/etc/mtab
sudo chroot /mnt/debian/ /bin/bash
grub-install
update-grub