bug#10740: 24.0.93; shell-command-on-region works via menu but not by keys

[Chong Yidong]

Thomas Rikl <trikl@online.de> writes:

> Highlight a region, try to filter it with "grep xzy" via menu [Tools,
> Shell Command on region] results in output in the minibuffer ok!
> Trying this with M-| and nothing (useful) happens?

For what it's worth, I can't reproduce this.  Latest trunk,
x86_64-unknown-linux-gnu:

emacs -Q
C-SPC
M-<
M-| grep th RET

The grepped lines are shown.

Please provide a more precise recipe.