where to do line editing?

[Doug Gwyn]

Terminal input editing belongs where the input is being done,
namely the terminal.  Rob Pike explained this to us at a USENIX
a few years ago; that's how my terminal operates and it works
great.  Neither the kernel nor the application programs are
aware of my editing (which can combine pieces from several
windows, typically snarfed with the mouse).  Foo on complicating
the I/O multiplexor, er, operating system!