What happens if you put
set blink-matching-paren off
in your ~/.inputrc file and restart Octave?
Alas, this doesn't work for me. I can reproduce the problem with simple
text without punctuation.
If I use the three lines below as a test then the first two are
processed instantly and the third takes a good long while to print
character by character.
--Cut--
this is very long text
this is very long text
this is very long text
--Paste--
The interaction is clearly between Readline and whatever else might be
using the readline loop. For example, I can start without the GUI (no
readline) and pasting text works. But if I execute 'graphics_toolkit
fltk' then subsequent pasting is slow. Returning to gnuplot after fltk
has been initialized does not clear the slow pasting so something
quasi-permanent is left in place.