Paul Eggert <egg...@cs.ucla.edu> wrote: > With recent 'grep' you can work around the problem by configuring > --with-included-regex.
Not so. I did a fresh ./boostrap ./configure --with-included-regex make and it still core dumps: $ echo abc | ./src/grep -E '(.*)(.*)(.*)\3\2\1' grep: regexec.c:1413: pop_fail_stack: Assertion `((Idx) (num) < ((Idx) -2))' failed. Aborted (core dumped) I looked at it in a debugger fs->num before the --fs->num executes looks to be -1. Thanks, Arnold