#+begin_example
echo 'abc :results output :eval no' | sed -E 's#.*(results [[:alnum:]]{1,}).*#\1#'
#+end_example

This demonstrates the following uses of GNU sed:

- Extended regexps :: =-E=
- Substitution :: =s#OLD#NEW#=
- Character classes :: =[[:alnum:]]=
- "bounds" :: ={1,0}= (could be =+=)
- replacement :: =s#(FOO)#\1#=