Using "+Left/Right" to move between words in an editing window
⌥ + arrow keys will let you navigate by word. As you said, ⌘ + arrow keys will move to the end/beginning of the line or document. Both of these can also be used with ⇧ to select, or the delete key. Furthermore, you can double-click to select a word and triple-click to select a paragraph — and if you double-click-drag or triple-click-drag, you can select multiple words or paragraphs.

Also useful, and perhaps familiar to you coming from Linux:


ctrl A moves to the beginning of a paragraph
ctrl E moves to the end of a paragraph
fn ⌫ deletes forwards (and can be combined with ⌘ or ⌥;
you can also use ctrlD which doesn't work with the other modifiers)
ctrl K deletes to the end of the paragraph (kill)
ctrl Y pastes that text back (yank)
ctrl L scrolls so the selected text is visible
ctrl T transposes the two characters next to the cursor
ctrl O inserts a newline after the cursor


More interesting shortcuts and uses of the keyboard can be found here and elsewhere on the internet.