Get Mac hardware model:

$ sudo dmidecode -s system-product-name
MacBookAir5,2

Show all S.M.A.R.T. info of a disk:

$ smartctl -a /dev/ada4

Low-level format of the hda device:

$ dd if=/dev/zero of=/dev/hda

Same as above but for paranoïd, as random bits will be written 3 times before performing the “low-level format” (i.e. writing zeros):

$ shred --verbose --force --iterations=3 --zero /dev/hda

Remove the MBR:

$ dd if=/dev/null of=/dev/hda bs=446 count=1

Restore the original Windows MBR:

$ apt-get install mbr
$ install-mbr -i n -p D -t 0 /dev/hda

Guess the partition table of a device, including damaged ones:

$ gpart -v /dev/md0

Search for a Linux partition:

$ sudo fdisk -d /dev/disk0 | cut -d ',' -f 3 | grep --quiet "0x83"
$ if [[ $? -ne 0 ]]; then
>     echo "No Linux partition found."
> else
>     echo "Linux partition found."
> fi

Mount an NTFS partition:

$ sudo ntfs-3g /dev/disk4s2 ./usb-hdd -o local -o allow_other -o auto_xattr -o auto_cache

Extract the content of an Apple Disk Image .dmg file and access its content:

$ dmg2img ./my-package.dmg
$ mount -t hfsplus -o loop ./my-package.img /media/my-mount-point

Change the keyboard layout in Debian (don’t forget to logoff and logon to activate the new setting):

$ dpkg-reconfigure keyboard-configuration

X.orgs’ configuration (~/.Xmodmap) to remap function and command keys of a Mac keyboard (source):

! --- Remove Cmd keys
! Remaps the keys (reading left-to-right):
!    -FROM-
!  Fn Control_L Alt_L Super_L Space Super_R Alt_R
!    -TO-
!  Fn Control_L Alt_L Alt_L Space Alt_R Alt_R
!
keycode 133 = Alt_L Meta_L Alt_L Meta_L
keycode 134 = ISO_Level3_Shift
clear Mod1
clear Mod4
clear Mod5
add Mod1 = Alt_L Alt_R Meta_L
add Mod4 = Super_L Super_R Super_L Hyper_L
add Mod5 = ISO_Level3_Shift Mode_switch

X.orgs’ configuration (~/.Xmodmap) to either set natural or reverse scrolling for Mac trackpads (source):

! --- Reverse Scrolling
!pointer = 1 2 3 5 4 6 7 8 9 10 11 12 13 14 15
! --- Natural Scrolling
pointer = 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

To add touchpad kernel support, add the following option to kernel at boot time:

$ psmouse.proto=imps

Sometimes, depending of the laptop I use, the mouse pointer disappear from the screen when I plug a VGA cable to a projector. In this case, I resort to a ++ctrl+alt+f1++, then I login as a normal user and finally I start a new X session:

$ startx -- :1

Get the number of shutter count of a DSLR (Canon EOS 7D in my case):

$ gphoto2 --get-config /main/status/shuttercounter
Label: Shutter Counter
Type: TEXT
Current: 49238

List printers:

$ lpstat -p -d
printer HP_Color_LaserJet_M254dw_0 is idle.  enabled since Fri Nov  6 17:47:06 2020
system default destination: HP_Color_LaserJet_M254dw_0

$ lpq
HP_Color_LaserJet_M254dw_0 is ready and printing
Rank    Owner   Job     File(s)                         Total Size
1st     kde     209     (stdin)                         0 bytes
active  kde     211     HP_Color_LaserJet_Pro_M254_dw_P 33557504 bytes
2nd     kde     212     HP_Color_LaserJet_Pro_M254_dw_P 33557504 bytes
3rd     kde     213     HP_Color_LaserJet_Pro_M254_dw_P 33557504 bytes