No, it *should not*, but it *does*, at least for me in an updated & dist-upgraded 32-bit version (up to date today).
Using the attached file: nio@xenial32 ~ $ cat seen-binary-by-grep.txt vMgs ingen l�sning - the Swedish character o-umlaut osmak ingen l�sning smak lösningen - the solution nio@xenial32 ~ $ grep ning seen-binary-by-grep.txt Binär fil seen-binary-by-grep.txt matchar nio@xenial32 ~ $ grep -a ning seen-binary-by-grep.txt vMgs ingen l�sning - the Swedish character o-umlaut osmak ingen l�sning smak lösningen - the solution nio@xenial32 ~ $ tail -n1 seen-binary-by-grep.txt|grep ning smak lösningen - the solution nio@xenial32 ~ $ head -n2 seen-binary-by-grep.txt|grep ning Binär fil (standard in) matchar nio@xenial32 ~ $ head -n2 seen-binary-by-grep.txt|grep -a ning vMgs ingen l�sning - the Swedish character o-umlaut osmak ingen l�sning nio@xenial32 ~ $ ** Attachment added: "seen-binary-by-grep.txt" https://bugs.launchpad.net/ubuntu/+source/grep/+bug/1535458/+attachment/4679678/+files/seen-binary-by-grep.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1535458 Title: [15.10 REGRESSION] Randomly wrongly detects files as binary To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grep/+bug/1535458/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs