The Compose key <http://wiki.wlug.org.nz/ComposeKey> is probably the best way of typing less common characters available on any OS. It lets you use mnemonic sequences that actually bear some relationship to the character you are trying to enter, instead of having to remember numeric codes. You will find there a list of the characters that I found most useful, though the complete set will be in the Compose file for your chosen locale. You can even add your own compose sequences. This tutorial for KDE <https://userbase.kde.org/Tutorials/ComposeKey/en> covers the procedure. Basically, you create a file “.XCompose” in your home directory, include a system Compose file to inherit the standard sequences, and put in extra compose-key definitions using the same syntax as the system Compose files. I had got this far, but then was baffled as to why KDE seemed to pay no attention whatsoever to my custom compose-key sequences. It turns out you need to define additional environment variables to get Qt/KDE- and GTK-based apps to use the X11 input method that actually reads the .XCompose file. Put these in your .bashrc: export GTK_IM_MODULE=xim export QT_IM_MODULE=xim and when you logout and login again, it should all work. For example, in my .XCompose, I have the line <Multi_key> <p> <i> which lets me type compose-p-i to produce “π”.