Literally the most useful keyboard shortcut I learned this year is ctrl + U
It deletes a filled password field on linux. In your browser, on the bootscreen when entering your LUKS password, your login password field, in the sudo prompt, …
It's great when you have a long password and you know you hit a typo somewhere.
Try it it's awesome. And it's the worst thing, that it doesn't work on other platforms.
@robjloranger I know what you mean. But just pressing ctrl + U is so much more convenient. Once you get used to it, it feels super complicated to clean password fields in any other way.
@sheogorath This is amazing!
@sheogorath Looks like it's a readline thing: http://readline.kablamo.org/emacs.html
Emacs bindings :)
@sheogorath that sounds handy
@pro Grandpas and their war stories 
"We didn't have such luxury back then, everything was made of stone and wood, even computers" 
@sheogorath Great finding!
Another handy shortcut you might like is Ctrl + Y (or ^Y), which yanks the text killed by ^U. It’s useful when you enter a command, recall you had to do something else quickly and kill that command, and later continue with the initial task.
Example:
$ make install ^U $ ed grocery.txt $a carrots . $ ^Y
After the ^Y at the end, you’d end up with the command make install re-entered. It’s also handy when you know you’d run several commands that start similar but have different last argument.
@sheogorath I have to test this in qutebrowser
Ctrl A - go to line beginning
Ctrl E - go to line end
And one more for shell users:
Alt # - transform current line in comment and insert it in history (then gives you a blank prompt)
@sheogorath that's amazing, I usually just mash backspace until it beeps at me