Unable to clear a beginning of a line by C-u in Emacs

Question

I run the following command in Emacs unsuccessfully

C-u

How can you clear the beginning of a line in Emacs?

Answer 1

You can also accomplish this by using a prefix arg for kill-ine (usually C-k). From the Emacs help (C-h k C-k):

With zero argument, kills the text before point on the current line.

So, you can do

C-u 0 C-k

or even better

C-0 C-k

Answer 2

You can set the mark, go to the beginning, kill till mark:

C-Spc C-a C-w