I was unable to recreate the problem given the test case provided and the following version of grep:
$ apt-cache policy grep grep: Installed: 2.23-1 Candidate: 2.23-1 Version table: *** 2.23-1 500 500 http://mirrors.cat.pdx.edu/ubuntu xenial/main amd64 Packages 100 /var/lib/dpkg/status ** Changed in: grep (Ubuntu) Status: New => Incomplete -- 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/1547466 Title: grep switches into binary mode while processing a text file Status in grep package in Ubuntu: Incomplete Bug description: I noticed this staring to happen in Xenial about two days ago. When running sbuild (or now the buildd, too), the build breaks when trying to compile a generated file. I traced the problem down to grep suddenly acting weird. When not having any language set (or a non-UTF8 mode) it will start printing some lines of a source file and then suddenly end that by printing "Binary file ... matches". With the attached file, the difference can be observed (running Xenial): LANG=C grep -v xxx grant_table.h and LANG=C.UTF-8 grep -v xxx grant_table.h To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grep/+bug/1547466/+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