|Ctrl + a||move to the beginning of the line|
|Ctrl + e||move to the end of the line|
|Ctrl + k||Kill the text from the current cursor position to the end of the line.|
|Ctrl + u||Kill the text from the current cursor position to the beginning of the line|
|Ctrl + w||Kill the word behind the current cursor position|
|Alt + b||move backward one word|
|Alt + f||move forward one word|
|Ctrl + Alt + e||shell expand line|
|Ctrl + y||Yank the most recently killed text back into the buffer at the cursor.|
|Alt + y||Rotate through killed text. You can only do this if the prior command is Ctrl + y or Alt + y.|
Killing text will delete text, but save it so that the user can reinsert it by yanking. Similar to cut and paste except that the text is placed on a kill ring which allows for storing more than one set of text to be yanked back on to the command line.
You can find out more in the emacs manual.