Readline

 To be clear, you don't want a "fast way to move the cursor on a terminal command line". What you   actually want is a fast way to navigate over command line in you shell program.

Bash is very common shell, for example. It uses Readline library to implement command line input.  And so to say, it is very convenient to know Readline bindings since it is used not only in bash. For example, gdb also uses Readline to process input.

In Readline documentation you can find all navigation related bindings (and more): http://www.gnu.org/software/bash/manual/bash.html#Readline-Interaction

Short copy-paste if the link above goes down:

Bare Essentials

C-b Move back on e character.
C-f Move forward one character.
[DEL] or [Backspace] Delete the character to the left of the cursor.
C-d Delete the character underneath the cursor.
C-_ or C-x C-u Undo the last editing command. You can undo all the way back to an empty line.

Movement

C-a Move to the start of the line.
C-e Move to the end of the line.
M-f Move forward a word, where a word is composed of letters and digits.
M-b Move backward a word.
C-l Clear the screen, reprinting the current line at the top.

Kill and yank

C-k Kill the text from the current cursor position to the end of the line.
M-d Kill from the cursor to the end of the current word, or, if between words, to the end of the next  word. Word boundaries are the same as those used by M-f.
M-[DEL] Kill from the cursor the start of the current word, or, if between words, to the start of the previous word. Word boundaries are the same as those used by M-b.
C-w Kill from the cursor to the previous whitespace. This is different than M- because the word boundaries differ.
C-y Yank the most recently killed text back into the buffer at the cursor.
M-y Rotate the kill-ring, and yank the new top. You can only do this if the prior command is C-y or  M-y.