This could be simplified a bit: vinc17@gcc92:~$ echo 11111111111 | grep --color=auto -E '^(11+)\1+$|^$' 11111111111
(nothing colored). -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to grep in Ubuntu. https://bugs.launchpad.net/bugs/1940996 Title: test failure - test-regex Status in grep: Fix Released Status in grep package in Ubuntu: New Bug description: 'test-regex' fails when building grep against glibc 2.34. Per commentary from grep upstream at https://debbugs.gnu.org/cgi/bugreport.cgi?bug=50069, the test failure can be attributed to skew between the glibc built-in regex and the one that is found in the grep source code. To manage notifications about this bug go to: https://bugs.launchpad.net/grep/+bug/1940996/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp