The most usable function I found for my mouse thumb button is actually Minimize window. When you combine it with Alt+Tab, it does wonders for fast window switching. Under Windows it’s trivial to configure this within Logitech Options. While not as easy in Linux, it’s actually not that hard either.

Since the Thumb button on most Logitech’s devices is not a mouse button but a key combination, we can use Ubuntu’s built-in Keyboard utility instead of remapping buttons. Or we can do it from command line equally easy:

$ gsettings set org.gnome.desktop.wm.keybindings minimize "['<Primary><Alt><Tab>']"

If you really want to have quick switching, you might want to also disable animations:

gsettings set org.gnome.desktop.interface enable-animations false

With those two changes you have your thumb button configured.

PS: And yes, this works for MX Master too.

M720 mouse has quite a few buttons. But remapping them under Linux is not necessarily the easiest thing in the world. For example, if one wants Forward and Backward buttons remapped to window left/right snap, there are a few things that need to be done manually.

First we need a few packages:

$ sudo apt install -y xbindkeys xautomation

Then we need to figure out which code our forward and backward keys are:

$ xev | grep -A 2 Button

In my case, these were 8 and 9 respectively.

Then we need to write mappings in ~/.xbindkeysrc:

"xte 'keydown Super_L' 'key Left' 'keyup Super_L'"
b:9

"xte 'keydown Super_L' 'key Right' 'keyup Super_L'"
b:8

And lastly, we need to restart xbindkeys:

$ killall xbindkeys 2>/dev/null
$ xbindkeys

If all went well, your buttons now know a new trick.

Booting ZFS Ubuntu of MBR is story I already told. But what if we want an encrypted UEFI ZFS setup?

Well, it’s quite simple to previous steps and again just a derivation on ZFS-on-Linux project.

As before, we first need to get into root prompt:

$ sudo -i

Followed by getting a few basic packages ready:

# apt-add-repository universe
# apt update
# apt install --yes debootstrap gdisk zfs-initramfs

Disk setup is quite simple with only two partitions:

# sgdisk --zap-all             /dev/disk/by-id/ata_disk

# sgdisk -n2:1M:+511M -t2:EF00 /dev/disk/by-id/ata_disk
# sgdisk -n1:0:0      -t1:8300 /dev/disk/by-id/ata_disk

# sgdisk --print               /dev/disk/by-id/ata_disk
Number  Start (sector)    End (sector)  Size       Code  Name
   1         1050624        67108830   31.5 GiB    8300
   2            2048         1050623   512.0 MiB   8300

I believe full disk encryption should be a no-brainer so of course we set up LUKS:

# cryptsetup luksFormat -qc aes-xts-plain64 -s 256 -h sha256 /dev/disk/by-id/ata_disk-part1
# cryptsetup luksOpen /dev/disk/by-id/ata_disk-part1 luks1

Creating ZFS stays the same as before:

# zpool create -o ashift=12 -O atime=off -O canmount=off -O compression=lz4 -O normalization=formD \
      -O xattr=sa -O mountpoint=none rpool /dev/mapper/luks1
# zfs create -o canmount=noauto -o mountpoint=/mnt/rpool/ rpool/system
# zfs mount rpool/system

Getting basic installation on our disks follows next:

# debootstrap cosmic /mnt/rpool/
# zfs set devices=off rpool
# zfs list

And then we setup EFI boot partition:

# mkdosfs -F 32 -n EFI /dev/disk/by-id/ata_disk-part2
# mount /dev/disk/by-id/ata_disk-part2 /mnt/rpool/boot/

We need to ensure boot partition auto-mounts:

# echo PARTUUID=$(blkid -s PARTUUID -o value /dev/disk/by-id/ata_disk-part2) /boot vfat noatime,nofail,x-systemd.device-timeout=1 0 1 >> /mnt/rpool/etc/fstab
# cat /mnt/rpool/etc/fstab

Before we start using anything, we should prepare a few necessary files:

# cp /etc/hostname /mnt/rpool/etc/hostname
# cp /etc/hosts /mnt/rpool/etc/hosts
# cp /etc/netplan/*.yaml /mnt/rpool/etc/netplan/
# sed '/cdrom/d' /etc/apt/sources.list > /mnt/rpool/etc/apt/sources.list

If you are dual-booting system with Windows, do consider turning off UTC BIOS time:

# echo UTC=no >> /mnt/rpool/etc/default/rc5

With chroot we can get the first taste of our new system:

# mount --rbind /dev  /mnt/rpool/dev
# mount --rbind /proc /mnt/rpool/proc
# mount --rbind /sys  /mnt/rpool/sys
# chroot /mnt/rpool/ /bin/bash --login

Now we can update our software:

# apt update

Imediatelly followed with locale and time zone setup:

# locale-gen --purge "en_US.UTF-8"
# update-locale LANG=en_US.UTF-8 LANGUAGE=en_US
# dpkg-reconfigure --frontend noninteractive locales

# dpkg-reconfigure tzdata

Now we install Linux image and basic ZFS boot packages:

# apt install --yes --no-install-recommends linux-image-generic
# apt install --yes zfs-initramfs

Since we’re dealing with encrypted data, our cryptsetup should be also auto mounted:

# apt install --yes cryptsetup

# echo "luks1 UUID=$(blkid -s UUID -o value /dev/disk/by-id/ata_disk-part1) none luks,discard,initramfs" >> /etc/crypttab
# cat /etc/crypttab

Now we get grub started:

# apt install --yes grub-efi-amd64

And update our boot environment again (seeing errors is nothing unusual):

# update-initramfs -u -k all

And then we finalize our grup setup:

# update-grub
# grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=ubuntu --recheck --no-floppy

Finally we get the rest of desktop system:

# apt-get install --yes ubuntu-desktop samba linux-headers-generic
# apt dist-upgrade --yes

We can omit creation of the swap dataset but I always find it handy:

# zfs create -V 4G -b $(getconf PAGESIZE) -o compression=off -o logbias=throughput -o sync=always \
      -o primarycache=metadata -o secondarycache=none rpool/swap
# mkswap -f /dev/zvol/rpool/swap
# echo "/dev/zvol/rpool/swap none swap defaults 0 0" >> /etc/fstab
# echo RESUME=none > /etc/initramfs-tools/conf.d/resume

If one is so inclined, /home directory can get a separate dataset too:

# rmdir /home
# zfs create -o mountpoint=/home rpool/data

Only remaining thing before restart is to create user:

# adduser user
# usermod -a -G adm,cdrom,dip,lpadmin,plugdev,sambashare,sudo user
# chown -R user:user /home/user

As install is ready, we can exit our chroot environment and reboot:

# exit
# reboot

You will get stuck after the password prompt as our mountpoint for system dataset is wrong. That’s easy to correct:

# zfs set mountpoint=/ rpool/system
# exit
# reboot

Assuming nothing went wrong, your UEFI system is now ready.

I wanted to process Unicode CSV file to extract the first two columns into JSON. With awk it seemed easy enough:

awk '
    BEGIN {
        FS=";"
        print "["
    }
    {
        print "  { \"code\": \"" $1 "\", \"description\": \"" $2 "\" },"
    }
    END {
        print "]"
    }
    ' UnicodeData.txt | less

This will give you ALMOST parsable output. One thing that will spoil it is the last “hanging” comma making the whole JSON invalid (albeit some parsers will still load it). And no, there is no way to tell awk to do something special with the last line as processing of the lines is done one-by-one and thus there is no telling which line is last at any give moment.

What we can do is tell awk to process lines with a single line delay:

awk '
    BEGIN {
        FS=";"
        print "["
    }
    NR>1 {
        print "    { \"code\": \"" code "\", \"description\": \"" description "\" },"
    }
    {
        code = $1
        description = $2
    }
    END {
        print "    { \"code\": \"" code "\", \"description\": \"" description "\" }"
        print "]"
    }
    ' UnicodeData.txt | less

This prints content starting from the second line (NR>1) and what we do in the main loop is just storing fields into our variables that’ll be read in the next iteration. Essentially what we have is a single line delay mechanism. To catch up with the last line we just print it out without trailing comma in END portion of our program.

Valid JSON at last.