"ed was a command-line editor that worked identically to the colon-commands in vi and vim—in fact, you can press Q to get into ed mode (then type vi to get back

"ed was a command-line editor that worked identically to the colon-commands in vi and vim—in fact, you can press Q to get into ed mode (then type vi to get back into vim)." This is wrong. Pressing Q in vi quits visual mode and returns you to ex(1). ex(1) precedes vi(1) and was an extended editor, based on ed(1). That's why the commands are similar, but not identical. And ed(1) isn't dead, it still is a command-line editor. :-)