invalid multibyte escape error

Status changed to 'Confirmed' because the bug affects multiple users.

Thanks for reporting.

I am able to reproduce this issue with whatweb 0.4.8~git20150507-1 on Ubuntu Wily. The interesting part is that I was not able to trigger this on Debian, which means it looks an Ubuntu-only issue, though I'm not sure how.

I have this bug in Kubuntu 15.10:

user$ whatweb --version
/usr/bin/whatweb: /usr/lib/ruby/vendor_ruby/rchardet/universaldetector.rb:39: invalid multibyte escape: /[\x80-\xFF]/ (SyntaxError)

user$ apt show ruby
Package: ruby
Priority: optional
Section: interpreters
Installed-Size: 36.9 kB
Maintainer: Ubuntu Developers <email address hidden>
Original-Maintainer: Antonio Terceiro <email address hidden>
Source: ruby-defaults
Version: 1:2.3.0+1
Replaces: irb, rdoc, rubygems
Provides: irb, rdoc, rubygems
Depends: ruby2.3
Suggests: ri, ruby-dev
Conflicts: ruby-activesupport-2.3, ruby-activesupport-3.2
Breaks: apt-listbugs (<< 0.1.6), rbenv (<= 0.4.0-1), ruby-debian (<< 0.3.8+b3), ruby-switch (<= 0.1.0)
Download-Size: 5,530 B
Homepage: http://www.ruby-lang.org/
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Supported: 5y
Task: kubuntu-desktop, kubuntu-full, edubuntu-desktop-gnome, ubuntustudio-fonts
APT-Manual-Installed: yes
APT-Sources: http://gb.archive.ubuntu.com/ubuntu/ xenial/main amd64 Packages
Description: Interpreter of object-oriented scripting language Ruby (default version)
 Ruby is the interpreted scripting language for quick and easy object-
 oriented programming. It has many features to process text files and to
 do system management tasks (as in perl). It is simple, straight-forward,
 and extensible.
 .
 This package is a dependency package, which depends on Debian's default
 Ruby version (currently v2.3).

user$ apt show ruby-rchardet
Package: ruby-rchardet
Priority: optional
Section: universe/ruby
Installed-Size: 497 kB
Maintainer: Ubuntu Developers <email address hidden>
Original-Maintainer: Debian Ruby Extras Maintainers <email address hidden>
Version: 1.3-3build1
Depends: ruby | ruby-interpreter
Download-Size: 91.7 kB
Homepage: http://github.com/jmhodges/rchardet/tree/master
Ruby-Versions: all
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
APT-Manual-Installed: no
APT-Sources: http://gb.archive.ubuntu.com/ubuntu/ xenial/universe amd64 Packages
Description: Character encoding auto-detection for Ruby
 CharDet is a library to automatically detect character encoding 'as smart
 as your browser'

Prepend the following line — it must be the first line in the file:

# encoding: US-ASCII

That solves the problem but there might be a cleaner solution.