If you need to resize a lot of images, doing it manually in Gimp is an option, but can take a long time.

In stead, you could do it from the command line, with the mogrify tool, which is included in imagemagick.

Install it like this:

Ubuntu 18.04 comes with a lot of variations of English, which can clutter the spellchecker in Thunderbird and Firefox.

A quick way of removing some of the variations of English, the safest method is uninstalling the unneeded language packages.

In my case, I had these in my /usr/share/hunspell folder:

Electrum is a light weight Bitcoin wallet. There are many advantages of using a Desktop wallet, as opposed to keeping your digital currency on an exchange, where you have less control. Another, and possibly safer solution, would be using a hardware wallet.

If your Ubuntu installation sometimes drops into a black screen showing something like /dev/sda1: clean, 227147/30269440 files, 3330843/121068288 blocks, try to get get back to your installation by pressing Alt+F2.

You might see a password prompt with this text:

Pyrenamer doesn't exist for Ubuntu 18.04, but GPRename is a similar GUI batch renamer app from the default Ubuntu repositories. To quickly open a program in Ubuntu, you can press the Super (Windows) key and start typing, but GPRename isn't added after installing it:

If you have switched graphic card driver from Nvidia to Nouveau in Ubuntu, you might get this message after boot, where it just hangs:

You can reduce the size of a video by reducing the resolution with the ffmpeg program.

Install:

sudo apt install ffmpeg

Lower the quality, for smaller files

Add for example -crf 26 to reduce the quality, where 23 is the default, 0 is lossless and 51 is worst quality.

Snap is a new experiment in Ubuntu 18.04, which makes the File System useless, as well as other annoyances like creating a folder in /home/username/Snap.

To uninstall Snap and reinstall the packages the normal way:

sudo apt purge snapd
sudo apt-get update
sudo apt-get install gnome-calculator gnome-characters gnome-logs gnome-system-monitor

If you have tried everything, but can't set VLC as default application for MP3's, last resort is to manually update ~/.config/mimeapps.list.

Setting files for Sublimetext are in this folder in Ubuntu: ~/.config/sublime-text-3/Packages/User

General settings
Insert this in ~/.config/sublime-text-3/Packages/User/Preferences.sublime-settings to change the skin, font size, tab size, convert tabs to spaces, etc. You might have to install the Solarized Color Scheme as a Package first: