This is fixed in Debian unstable as well as in the next version of Ubuntu (16.04).
So I recommend you install https://launchpad.net/ubuntu/+source/rkhunter/1.4.2-4 ** Bug watch added: Debian Bug tracker #791486 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=791486 ** Also affects: rkhunter (Debian) via http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=791486 Importance: Unknown Status: Unknown ** Changed in: rkhunter (Ubuntu) Status: New => Fix Committed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1509663 Title: “[: Binary: unexpected operator” message when updating rkhunter definitions To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/rkhunter/+bug/1509663/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs