From Knowledgebase


Offline dictionary - GoldenDict


Install the GoldenDict dictionary application for your Linux distribution.

By default, the application only seems to use online dictionaries for English to English dictionaries.

Download the free offline dictionary Wordnet3 from here.

Unzip the downloaded file and place the file that ends with .dz in /usr/share/dictd

Now open GoldenDict. Go to Edit -> Dictionaries (or press F3). Under the Sources -> Files, you'll see the directories that GoldenDict looks for dictionary files. Press the "Rescan now" button in the right pane to index the newly added dictionary.

Optional: You can also make WordNet3 the dictionary with the highest priority by dragging it to the top in the Dictionaries tab.

Network Tricks

Connecting to two networks - one Wi-Fi and one wired

Wi-Fi network has internet, wired does not. Then, disable the gateway of the Wired network for internet access.

Show the networks

$ ip route show

Smaller metric number means higher priority for the gateway

Remove the gateway of the wired network

$ sudo ip route del default via

chroot into a Raspberry Pi

Mount sequence

mount /dev/sdb3 /mnt
mount /dev/sdb2 /mnt/boot
mount /dev/sdb1 /mnt/boot/firmware
mount -o bind /proc /mnt/proc
mount -o bind /sys /mnt/sys
mount -o bind /dev /mnt/dev
mount -o bind /dev/pts /mnt/dev/pts
cp /usr/bin/qemu-arm-static /mnt/usr/bin
chroot /mnt

Doing stuff in chroot

Example: Fixing a broken apt install

dpkg --configure -a
apt -f install

Unmount sequence

umount /mnt/dev/pts
umount /mnt/dev/
umount /mnt/sys
umount /mnt/proc
umount /mnt/boot/firmware
umount /mnt/boot/
umount /mnt

Gnome tricks

Creating a desktop launcher on Gnome

Install gnome-panel

sudo apt-get install --no-install-recommends gnome-panel

Open the Create Launcher dialog and enter the details for the launcher

sudo gnome-desktop-item-edit --create-new /usr/share/applications


Trimming a video

ffmpeg can be used to trim a video from a given start time to end time.

ffmpeg -i video.webm -ss 00:00:00 -t 00:05:04 -async 1 video-cut.webm

Create ebook from a website using Calibre

Some free books on the internet are available as HTML pages.
An epub file is simply an archive of HTML pages that can be treated as an ebook.
A book website can be stitched into an ebook using wget and calibre

wget -r --no-parent
ebook-convert index.html hpmor.epub

X Window system tricks

Switch to Colemak layout in X window system

setxkbmap us -variant colemak

Natural scrolling

Run the following command, then logout and login.

echo "pointer = 1 2 3 5 4 6 7 8 9 10 11 12" >> ~/.Xmodmap

VirtualBox tricks

Adding a new virtual USB disk to a virtual machine

  • Enable USB controller for the virtual machine. This can be done from the VirtualBox UI.
  • Create a new virtual disk and add it using the USB controller.
  • Run this command as root inside the box.
   # mkfs.ext4 /dev/sdb