GNU bug report logs - #21461
grep --color can leave terminal in weird state after signal

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To: grep bugs <bug-grep@HIDDEN>
From: Paul Eggert <eggert@HIDDEN>
Subject: grep --color can leave terminal in weird state after signal
Organization: UCLA Computer Science Department
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If grep --color is interrupted, either via ^C or ^Z or some other signal, it can 
leave the output terminal in a weird state.  This problem was noted by Giuseppe 
Scrivano in <http://bugs.gnu.org/20062#143> and I'm forwarding the report here. 
  One fix would be to do what GNU 'ls' does; note that SIGTSTP must be treated 
specially so that the color state resumes after restart; also, the signal 
handler just sets a flag that is polled periodically by the main code.