diff --git a/.travis.yml b/.travis.yml
index ac6800a7..7b013349 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,7 @@ before_install:
   - git fetch origin master:master
   - git fetch origin v2.0.0:v2.0.0
   - git fetch origin test/attributes:test/attributes
+  - git fetch origin test/master:test/master
   - sudo apt-get install libicu-dev -y
 rvm:
   - 1.9.3
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index ee13ae71..d0884dab 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -12,7 +12,7 @@ This can usually be solved either by adding a new filename or file name extensio
 
 Assuming your code is being detected as the right language (see above), in most cases this is due to a bug in the language grammar rather than a bug in Linguist. [`grammars.yml`][grammars] lists all the grammars we use for syntax highlighting on github.com. Find the one corresponding to your code's programming language and submit a bug report upstream.
 
-You can also try to fix the bug yourself and submit a Pull Request. [This piece from TextMate's documentation](http://manual.macromates.com/en/language_grammars) offers a good introduction on how to work with TextMate-compatible grammars.
+You can also try to fix the bug yourself and submit a Pull Request. [This piece from TextMate's documentation](http://manual.macromates.com/en/language_grammars) offers a good introduction on how to work with TextMate-compatible grammars. You can test grammars using [Lightshow](https://lightshow.githubapp.com).
 
 Once the bug has been fixed upstream, please let us know and we'll pick it up for GitHub.
 
diff --git a/Gemfile b/Gemfile
index 481a4c6e..95769569 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,3 +2,4 @@ source 'https://rubygems.org'
 gemspec :name => "github-linguist"
 gemspec :name => "github-linguist-grammars"
 gem 'test-unit', require: false if RUBY_VERSION >= '2.2'
+gem 'byebug' if RUBY_VERSION >= '2.0'
diff --git a/github-linguist.gemspec b/github-linguist.gemspec
index 463275f2..578e823c 100644
--- a/github-linguist.gemspec
+++ b/github-linguist.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'charlock_holmes', '~> 0.7.3'
   s.add_dependency 'escape_utils',    '~> 1.0.1'
   s.add_dependency 'mime-types',      '>= 1.19'
-  s.add_dependency 'rugged',          '~> 0.22.0b1'
+  s.add_dependency 'rugged',          '~> 0.22.0b4'
 
   s.add_development_dependency 'mocha'
   s.add_development_dependency 'pry'
diff --git a/grammars.yml b/grammars.yml
index 15aeb74c..ce126d70 100644
--- a/grammars.yml
+++ b/grammars.yml
@@ -5,8 +5,6 @@ http://svn.textmate.org/trunk/Review/Bundles/BlitzMax.tmbundle:
 - source.blitzmax
 http://svn.textmate.org/trunk/Review/Bundles/Cython.tmbundle:
 - source.cython
-http://svn.textmate.org/trunk/Review/Bundles/F%20Sharp.tmbundle:
-- source.fsharp
 http://svn.textmate.org/trunk/Review/Bundles/Forth.tmbundle:
 - source.forth
 http://svn.textmate.org/trunk/Review/Bundles/Parrot.tmbundle:
@@ -137,6 +135,8 @@ https://github.com/fancy-lang/fancy-tmbundle:
 - source.fancy
 https://github.com/fushnisoft/SublimeClarion:
 - source.clarion
+https://github.com/fsharp/fsharpbinding:
+- source.fsharp
 https://github.com/gingerbeardman/monkey.tmbundle:
 - source.monkey
 https://github.com/guillermooo/dart-sublime-bundle/raw/master/Dart.tmLanguage:
diff --git a/lib/linguist/file_blob.rb b/lib/linguist/file_blob.rb
index bc475023..04441935 100644
--- a/lib/linguist/file_blob.rb
+++ b/lib/linguist/file_blob.rb
@@ -57,14 +57,20 @@ module Linguist
     #
     # Returns a String.
     def extension
-      # File.extname returns nil if the filename is an extension.
-      extension = File.extname(name)
-      basename = File.basename(name)
-      # Checks if the filename is an extension.
-      if extension.empty? && basename[0] == "."
-        basename
-      else
-        extension
+      extensions.last || ""
+    end
+
+    # Public: Return an array of the file extensions
+    #
+    #     >> Linguist::FileBlob.new("app/views/things/index.html.erb").extensions
+    #     => [".html.erb", ".erb"]
+    #
+    # Returns an Array
+    def extensions
+      basename, *segments = File.basename(name).split(".")
+
+      segments.map.with_index do |segment, index|
+        "." + segments[index..-1].join(".")
       end
     end
   end
diff --git a/lib/linguist/language.rb b/lib/linguist/language.rb
index f4c7a62e..daa1d003 100644
--- a/lib/linguist/language.rb
+++ b/lib/linguist/language.rb
@@ -106,40 +106,52 @@ module Linguist
       # A bit of an elegant hack. If the file is executable but extensionless,
       # append a "magic" extension so it can be classified with other
       # languages that have shebang scripts.
-      extension = FileBlob.new(name).extension
-      if extension.empty? && blob.mode && (blob.mode.to_i(8) & 05) == 05
+      extensions = FileBlob.new(name).extensions
+      if extensions.empty? && blob.mode && (blob.mode.to_i(8) & 05) == 05
         name += ".script!"
       end
 
-      # First try to find languages that match based on filename.
+      # Find languages that match based on filename.
       possible_languages = find_by_filename(name)
 
-      # If there is more than one possible language with that extension (or no
-      # extension at all, in the case of extensionless scripts), we need to continue
-      # our detection work
-      if possible_languages.length > 1
-        data = blob.data
-        possible_language_names = possible_languages.map(&:name)
-        heuristic_languages = Heuristics.find_by_heuristics(data, possible_language_names)
+      if possible_languages.length == 1
+        # Simplest and most common case, we can just return the one match based
+        # on extension
+        possible_languages.first
 
-        if heuristic_languages.size > 1
-          possible_language_names = heuristic_languages.map(&:name)
-        end
+      # If there is more than one possible language with that extension (or no
+      # extension at all, in the case of extensionless scripts), we need to
+      # continue our detection work
+      else
+        # Matches possible_languages.length == 0 || possible_languages.length > 0
+        data = blob.data
 
         # Check if there's a shebang line and use that as authoritative
         if (result = find_by_shebang(data)) && !result.empty?
-          result.first
-        # No shebang. Still more work to do. Try to find it with our heuristics.
-        elsif heuristic_languages.size == 1
-          heuristic_languages.first
-        # Lastly, fall back to the probabilistic classifier.
-        elsif classified = Classifier.classify(Samples.cache, data, possible_language_names).first
-          # Return the actual Language object based of the string language name (i.e., first element of `#classify`)
-          Language[classified[0]]
+          return result.first
+
+        # More than one language with that extension. We need to make a choice.
+        elsif possible_languages.length > 1
+
+          # First try heuristics
+
+          possible_language_names = possible_languages.map(&:name)
+          heuristic_languages = Heuristics.find_by_heuristics(data, possible_language_names)
+
+          # If there are multiple possible languages returned from heuristics
+          # then reduce language candidates for Bayesian classifier here.
+          if heuristic_languages.size > 1
+            possible_language_names = heuristic_languages.map(&:name)
+          end
+
+          if heuristic_languages.size == 1
+            return heuristic_languages.first
+          # Lastly, fall back to the probabilistic classifier.
+          elsif classified = Classifier.classify(Samples.cache, data, possible_language_names).first
+            # Return the actual Language object based of the string language name (i.e., first element of `#classify`)
+            return Language[classified[0]]
+          end
         end
-      else
-        # Simplest and most common case, we can just return the one match based on extension
-        possible_languages.first
       end
     end
 
@@ -190,8 +202,13 @@ module Linguist
     # Returns all matching Languages or [] if none were found.
     def self.find_by_filename(filename)
       basename = File.basename(filename)
-      extname = FileBlob.new(filename).extension
-      (@filename_index[basename] + find_by_extension(extname)).compact.uniq
+
+      # find the first extension with language definitions
+      extname = FileBlob.new(filename).extensions.detect do |e|
+        !@extension_index[e].empty?
+      end
+
+      (@filename_index[basename] + @extension_index[extname]).compact.uniq
     end
 
     # Public: Look up Languages by file extension.
diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index f3a74665..050e7dcf 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -470,6 +470,7 @@ CoffeeScript:
   extensions:
   - .coffee
   - ._coffee
+  - .cjsx
   - .cson
   - .iced
   filenames:
@@ -566,6 +567,8 @@ Crystal:
   - .cr
   ace_mode: ruby
   tm_scope: source.ruby
+  interpreters:
+  - crystal
 
 Cucumber:
   extensions:
@@ -743,6 +746,8 @@ Erlang:
   - .es
   - .escript
   - .hrl
+  interpreters:
+  - escript
 
 F#:
   type: programming
@@ -938,6 +943,8 @@ Gnuplot:
   - .gnuplot
   - .plot
   - .plt
+  interpreters:
+  - gnuplot
 
 Go:
   type: programming
@@ -1203,6 +1210,8 @@ Ioke:
   color: "#078193"
   extensions:
   - .ik
+  interpreters:
+  - ioke
 
 Isabelle:
   type: programming
@@ -1710,6 +1719,8 @@ Nu:
   filenames:
   - Nukefile
   tm_scope: source.scheme
+  interpreters:
+  - nush
 
 NumPy:
   group: Python
@@ -1896,6 +1907,8 @@ Parrot Assembly:
   - pasm
   extensions:
   - .pasm
+  interpreters:
+  - parrot
   tm_scope: none
 
 Parrot Internal Representation:
@@ -1906,6 +1919,8 @@ Parrot Internal Representation:
   - pir
   extensions:
   - .pir
+  interpreters:
+  - parrot
 
 Pascal:
   type: programming
@@ -1948,6 +1963,8 @@ Perl6:
   - .p6m
   - .pl6
   - .pm6
+  interpreters:
+  - perl6
   tm_scope: none
 
 PigLatin:
@@ -2012,6 +2029,8 @@ Prolog:
   - .ecl
   - .pro
   - .prolog
+  interpreters:
+  - swipl
 
 Propeller Spin:
   type: programming
@@ -2075,6 +2094,8 @@ Python:
   - wscript
   interpreters:
   - python
+  - python2
+  - python3
 
 Python traceback:
   type: data
@@ -2095,6 +2116,8 @@ QMake:
   extensions:
   - .pro
   - .pri
+  interpreters:
+  - qmake
 
 R:
   type: programming
@@ -2249,6 +2272,8 @@ Ruby:
   - .watchr
   interpreters:
   - ruby
+  - macruby
+  - rake
   filenames:
   - .pryrc
   - Appraisals
@@ -2335,6 +2360,8 @@ Scala:
   - .scala
   - .sbt
   - .sc
+  interpreters:
+  - scala
 
 Scaml:
   group: HTML
diff --git a/lib/linguist/samples.rb b/lib/linguist/samples.rb
index 82c011b1..001204b5 100644
--- a/lib/linguist/samples.rb
+++ b/lib/linguist/samples.rb
@@ -52,14 +52,16 @@ module Linguist
               })
             end
           else
+            path = File.join(dirname, filename)
+
             if File.extname(filename) == ""
-              raise "#{File.join(dirname, filename)} is missing an extension, maybe it belongs in filenames/ subdir"
+              raise "#{path} is missing an extension, maybe it belongs in filenames/ subdir"
             end
 
             yield({
-              :path     => File.join(dirname, filename),
+              :path     => path,
               :language => category,
-              :interpreter => File.exist?(filename) ? Linguist.interpreter_from_shebang(File.read(filename)) : nil,
+              :interpreter => Linguist.interpreter_from_shebang(File.read(path)),
               :extname  => File.extname(filename)
             })
           end
@@ -131,18 +133,19 @@ module Linguist
 
       script = script == 'env' ? tokens[1] : script
 
-      # "python2.6" -> "python"
-      if script =~ /((?:\d+\.?)+)/
-        script.sub! $1, ''
-      end
+      # If script has an invalid shebang, we might get here
+      return unless script
+
+      # "python2.6" -> "python2"
+      script.sub! $1, '' if script =~ /(\.\d+)$/
 
       # Check for multiline shebang hacks that call `exec`
       if script == 'sh' &&
         lines[0...5].any? { |l| l.match(/exec (\w+).+\$0.+\$@/) }
         script = $1
       end
-
-      script
+      
+      File.basename(script)
     else
       nil
     end
diff --git a/samples/CoffeeScript/example.cjsx b/samples/CoffeeScript/example.cjsx
new file mode 100644
index 00000000..def9cf2f
--- /dev/null
+++ b/samples/CoffeeScript/example.cjsx
@@ -0,0 +1,40 @@
+###* @cjsx React.DOM ###
+define 'myProject.ReactExampleComponent', [
+  'React'
+  'myProject.ExampleStore'
+  'myProject.ExampleActions'
+  'myProject.ReactExampleTable'
+], (React, ExampleStore, ExampleActions, ReactExampleTable ) ->
+
+  ReactExampleComponent = React.createClass
+    mixins: [ListenMixin]
+
+    getInitialState: ->
+      rows: ExampleStore.getRows()
+      meta: ExampleStore.getMeta()
+
+    componentWillMount: ->
+      @listenTo ExampleStore
+
+    componentDidMount: ->
+      ExampleActions.getExampleData()
+
+    onStoreChange: ->
+      if this.isMounted()
+        @setState
+          rows: ExampleStore.getRows()
+          meta: ExampleStore.getMeta()
+
+    componentWillUnmount: ->
+      @stopListening ExampleStore
+
+    render: ->
+      <div className="page-wrap">
+          <header>
+            <strong> {@state.title} </strong>
+          <header>
+            <ReactExampleTable
+              rows={@state.rows},
+              meta={@state.meta}
+            />
+      </div>
diff --git a/samples/PHP/drupal.module b/samples/PHP/drupal.script!
similarity index 100%
rename from samples/PHP/drupal.module
rename to samples/PHP/drupal.script!
diff --git a/samples/Ruby/wrong_shebang.rb b/samples/Ruby/wrong_shebang.rb
deleted file mode 100644
index 22b4804a..00000000
--- a/samples/Ruby/wrong_shebang.rb
+++ /dev/null
@@ -1,2 +0,0 @@
-#!/usr/bin/env python
-puts "Not Python"
diff --git a/test/fixtures/Python/run_tests.module b/test/fixtures/Python/run_tests.module
new file mode 100644
index 00000000..b3d004e6
--- /dev/null
+++ b/test/fixtures/Python/run_tests.module
@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+import sys, os
+
+# Set the current working directory to the directory where this script is located
+os.chdir(os.path.abspath(os.path.dirname(sys.argv[0])))
+
+#### Set the name of the application here and moose directory relative to the application
+app_name = 'stork'
+
+MODULE_DIR = os.path.abspath('..')
+MOOSE_DIR = os.path.abspath(os.path.join(MODULE_DIR, '..'))
+#### See if MOOSE_DIR is already in the environment instead
+if os.environ.has_key("MOOSE_DIR"):
+  MOOSE_DIR = os.environ['MOOSE_DIR']
+
+sys.path.append(os.path.join(MOOSE_DIR, 'python'))
+import path_tool
+path_tool.activate_module('TestHarness')
+
+from TestHarness import TestHarness
+# Run the tests!
+TestHarness.buildAndRun(sys.argv, app_name, MOOSE_DIR)
diff --git a/test/fixtures/Shell/mintleaf.module b/test/fixtures/Shell/mintleaf.module
new file mode 100644
index 00000000..2f80f259
--- /dev/null
+++ b/test/fixtures/Shell/mintleaf.module
@@ -0,0 +1,1505 @@
+#!/bin/bash
+
+################################################################################
+## base routines
+##
+
+function list_modules() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Show all modules.
+
+    PARAMETERS:
+        -e|--enabled show enabled modules only
+        -d|--disabled show disabled modules only
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get additional parameters
+    local option=
+    while [ "$1" != "" ]; do
+        case $1 in
+            -e|--enabled)   option="-e"
+                            ;;
+            -d|--disabled)  option="-d"
+                            ;;
+        esac
+        shift
+    done
+
+    _list_modules $option
+}
+
+function print_module_info() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Show module description.
+
+    PARAMETERS:
+        \$1 module name
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local module=${1-mintleaf}
+
+    if [ $(list_modules | grep $module | wc -l) -eq 1 ]; then
+        if [ -f $MINTLEAF_HOME/modules/$module/$module.md ]; then
+            printf "\n"
+            cat $MINTLEAF_HOME/modules/$module/$module.md 2> /dev/null
+            printf "\n"
+        fi
+    else
+        echo "Module does not exist"
+    fi
+}
+
+function list_functions() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Show all available functions for given module.
+
+    PARAMETERS:
+        \$1 module name
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    _list_functions $1
+}
+
+function create_module() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Create module along with its essential files.
+
+    PARAMETERS:
+        \$1 module name
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local module=$1
+
+    mkdir $MINTLEAF_HOME/modules/$module
+
+    [ ! -f $MINTLEAF_HOME/modules/$module/$module.md ] && cat << EOF >> $MINTLEAF_HOME/modules/$module/$module.md
+$module
+=======
+
+TODO
+EOF
+    [ ! -f $MINTLEAF_HOME/modules/$module/$module.config ] && cat << EOF >> $MINTLEAF_HOME/modules/$module/$module.config
+EOF
+    [ ! -f $MINTLEAF_HOME/modules/$module/$module.install ] && cat << EOF >> $MINTLEAF_HOME/modules/$module/$module.install
+#!/bin/bash
+
+function install_module() {
+
+    echo "TODO"
+}
+EOF
+    [ ! -f $MINTLEAF_HOME/modules/$module/$module.module ] && cat << EOF >> $MINTLEAF_HOME/modules/$module/$module.module
+#!/bin/bash
+EOF
+    [ ! -f $MINTLEAF_HOME/modules/$module/$module.test ] && cat << EOF >> $MINTLEAF_HOME/modules/$module/$module.test
+#!/bin/bash
+
+function test_prerequisites() {
+
+    echo "TODO"
+}
+
+function test_module() {
+
+    assert_prerequisites
+
+    echo "TODO"
+}
+EOF
+    [ ! -f $MINTLEAF_HOME/modules/$module/$module.groovy ] && cat << EOF >> $MINTLEAF_HOME/modules/$module/$module.groovy
+EOF
+}
+
+################################################################################
+## general routines
+##
+
+function func_exists() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if function exists.
+
+    PARAMETERS:
+        \$1 function name
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local func=$1
+
+    declare -f -F $func > /dev/null
+    if [ "$?" == "0" ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function usleep() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Sleep in increments of milliseconds.
+
+    PARAMETERS:
+        \$1 milliseconds
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local ms=$1
+    local sec=$(echo "scale=2; $ms / 1000" | bc)
+
+    perl -e "select(undef,undef,undef,$sec)"
+}
+
+function h2d() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Convert hexadecimal to decimal number.
+
+    PARAMETERS:
+        \$1 hexadecimal number
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local hex=$1
+
+    hex=$(upper $hex)
+    local dec=$(echo "ibase=16; $hex" | bc)
+    echo $dec
+}
+
+function d2h() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Convert decimal to hexadecimal number.
+
+    PARAMETERS:
+        \$1 decimal number
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local dec=$1
+
+    local hex=$(echo "ibase=10; obase=16; $dec" | bc)
+    hex=$(lower $hex)
+    echo $hex
+}
+
+function random() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Return random string (A-Za-z0-9) with the given length.
+
+    PARAMETERS:
+        \$1 length
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local len=$1
+
+    local str=
+    str=</dev/urandom tr -dc A-Za-z0-9 | (head -c $ > /dev/null 2>&1 || head -c $len)
+    echo $str
+}
+
+function trim() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Remove whitespaces from the beginning and the end of a string.
+
+    PARAMETERS:
+        \$1 string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str="$1"
+
+    str=$(sed -e 's/^[[:space:]]*//' <<<"$str")
+    str=$(sed -e 's/[[:space:]]*$//' <<<"$str")
+    echo "$str"
+}
+
+function lower() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Convert string to lower case.
+
+    PARAMETERS:
+        \$1 string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str="$1"
+
+    str=$(echo $str | tr '[:upper:]' '[:lower:]')
+    echo "$str"
+}
+
+function upper() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Convert string to upper case.
+
+    PARAMETERS:
+        \$1 string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str="$1"
+
+    str=$(echo $str | tr '[:lower:]' '[:upper:]')
+    echo "$str"
+}
+
+function str_sanitise() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Sanitise string to meet certain criteria.
+
+    PARAMETERS:
+        \$1 string
+        \$2 character to be used as a replacement
+        --allowed-characters <characters>
+        --max-length <length>
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local char=$2
+
+    # get optional parameters
+    local allowed_characters=
+    local max_length=255
+    if [ "$3" != "" ] && [ "$3" != "--allowed-characters" ]; then
+        len=$3
+    fi
+    while [ "$1" != "" ]; do
+        case $1 in
+            --allowed-characters)   shift; allowed_characters=$1
+                                    ;;
+            --max-length)           shift; max_length=$1
+                                    ;;
+        esac
+        shift
+    done
+
+    # remove unwanted characters
+    local sanitised=$(echo $str | sed "s/[^A-Za-z0-9$allowed_characters]/$char/g")
+    # remove multiple instances of the replacement character
+    sanitised=$(echo $sanitised | sed -r "s/($char)+/$char/g")
+    # limit the length
+    sanitised=$(echo $sanitised | cut -c1-${max_length})
+    # make it lower case
+    echo $sanitised | tr '[:upper:]' '[:lower:]'
+}
+
+function str_substring() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Return substring by removing its prefix and suffix.
+
+    PARAMETERS:
+        \$1 string
+        \$2 prefix
+        \$3 suffix
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 3 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local pre=$2
+    local suf=$3
+
+    local str="${str#${str%${pre}*}${pre}}"
+    echo "${str%${suf}*}"
+}
+
+function str_contains() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if string contains another string.
+
+    PARAMETERS:
+        \$1 string
+        \$2 search string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local search=$2
+
+    local count=$(echo "$str" | grep "$search" | wc -l)
+    if [ $count -gt 0 ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function str_begins() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if string begins with another string.
+
+    PARAMETERS:
+        \$1 string
+        \$2 search string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local search=$2
+
+    local count=$(echo "$str" | grep "^$search" | wc -l)
+    if [ $count -eq 1 ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function str_ends() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if string ends with another string.
+
+    PARAMETERS:
+        \$1 string
+        \$2 search string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local search=$2
+
+    local count=$(echo "$str" | grep "$search$" | wc -l)
+    if [ $count -eq 1 ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function str_split_part() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Split string and return part given by the third argument.
+
+    PARAMETERS:
+        \$1 string
+        \$2 separator
+        \$3 part (index starts from 1)
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 3 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local separator=$2
+    local part=$3
+
+    echo $(echo $str | awk '{ split($str,a,v1); print a[v2]; }' v1=$separator v2=$part)
+}
+
+function str_compare_ver() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Compare two version strings.
+
+    PARAMETERS:
+        \$1 version
+        \$2 version
+
+    RETURN: -1, 0 or 1 as the first argument is less than, equal to or greater than the second.
+HEREDOC
+)
+
+    if [[ $1 == $2 ]]; then
+        echo 0
+        return
+    fi
+
+    local ver1a=$(echo $1 | grep -oEi '[0-9\.]*' | head -1)
+    local ver1b=$(str_substring $1 $ver1a "")
+    local ver2a=$(echo $2 | grep -oEi '[0-9\.]*' | head -1)
+    local ver2b=$(str_substring $2 $ver2a "")
+
+    local IFS=.
+    local i ver1=($ver1a) ver2=($ver2a)
+
+    # test the 1st part
+    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++)); do
+        ver1[i]=0
+    done
+    for ((i=0; i<${#ver1[@]}; i++)); do
+        if [[ -z ${ver2[i]} ]]; then
+            ver2[i]=0
+        fi
+        if ((10#${ver1[i]} > 10#${ver2[i]})); then
+            echo 1
+            return
+        fi
+        if ((10#${ver1[i]} < 10#${ver2[i]})); then
+            echo -1
+            return
+        fi
+    done
+
+    # test the 2nd part
+    if [ "$ver1b" \< "$ver2b" ]; then
+        echo -1
+        return
+    elif [ "$ver1b" \> "$ver2b" ]; then
+        echo 1
+        return
+    fi
+
+    echo 0
+}
+
+################################################################################
+## file routines
+##
+
+function file_escape_name() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Escape file name using the same way bash does it.
+
+    PARAMETERS:
+        \$1 string
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+
+    echo $(printf '%q' "$str" | sed s/=/\\\\=/g)
+}
+
+function file_contains() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if file contains given string.
+
+    PARAMETERS:
+        \$1 string to search for (regular expression matching multiple lines)
+        \$2 file name
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local file=$2
+
+    local count=$(cat $file | pcregrep -M "$str" | wc -l)
+    if [ $count -gt 0 ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function file_replace_str() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Replace string in given file.
+
+    PARAMETERS:
+        \$1 string to search for
+        \$2 new string
+        \$3 file name
+        -m|--multiline
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 3 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str1=$1
+    local str2=$2
+    local file=$3
+
+    # get optional parameters
+    local multiline="n"
+    while [ "$1" != "" ]; do
+        case $1 in
+            -m|--multiline) shift; multiline="y"
+                            ;;
+        esac
+        shift
+    done
+
+    local tmp_file=~/file_replace_str.$$
+    if [ $multiline == "y" ]; then
+        cat $file | perl -0777 -pe "s/$str1/$str2/igs" > $tmp_file
+    else
+        sed "s/$str1/$str2/g" $file > $tmp_file
+    fi
+    mv $tmp_file $file
+}
+
+function file_remove_str() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Remove string from given file.
+
+    PARAMETERS:
+        \$1 string to remove
+        \$2 file name
+        -m|--multiline
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local file=$2
+
+    # get optional parameters
+    local multiline="n"
+    if [ "$3" == "-m" ] || [ "$3" == "--multiline" ]; then
+        multiline="y"
+    fi
+
+    local tmp_file=~/file_remove_str.$$
+    if [ $multiline == "y" ]; then
+        cat $file | perl -0777 -pe "s/$str//igs" > $tmp_file
+    else
+        str='1h;1!H;${;g;s/'
+        sed -n "$str$1//g;p;}" $file > $tmp_file
+    fi
+    mv $tmp_file $file
+}
+
+function file_download() {
+
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Download file from given URL address.
+
+    PARAMETERS:
+        --url <url>                         URL address of file to download (required).
+        --file <name>                       Name of output file.
+        --cache-dir <dir>                   Cache directory; file name in that directory
+                                            must match the file name given as the parameter.
+        --donwload-directory <directory>    Destination directory where file
+                                            should be placed after download.
+        --size <size>                       Check file size after download.
+        --hash <hash>                       Check file hash after download.
+        --hash-algorithm <algorithm>        Hash algorithm used to check file.
+        --do-not-cache                      Do not cache file locally.
+        --force                             Force to download from given URL address not
+                                            using cached file or an alternative location.
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 4 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # variables
+    local url=
+    local file=
+    local cache_dir=$mintleaf_tmp_dir
+    local download_dir=./
+    local expected_size=0
+    local expected_hash=
+    local hash_algorithm="md5"
+    local do_not_cache=$result_neg
+    local force=$result_neg
+    local current_dir=$(pwd)
+
+    # get parameters
+    while [ "$1" != "" ]; do
+        case $1 in
+            --url)                  shift; url=$1
+                                    ;;
+            --file)                 shift; file=$1
+                                    ;;
+            --cache-dir)            shift; cache_dir=$1
+                                    ;;
+            --download-directory)   shift; download_dir=$1
+                                    ;;
+            --size)                 shift; expected_size=$1
+                                    ;;
+            --hash)                 shift; expected_hash=$1
+                                    ;;
+            --hash-algorithm)       shift; hash_algorithm=$1
+                                    ;;
+            --do-not-cache)         do_not_cache=$result_pos
+                                    ;;
+            --force)                force=$result_pos
+                                    ;;
+        esac
+        shift
+    done
+
+    # file may have already been downloaded
+    if [ $force == $result_neg ] && [ -s $cache_dir/$file ] && [ ! -s $download_dir/$file ]; then
+
+        cp -f $cache_dir/$file $download_dir
+
+    else
+
+        # download from local network
+        # TODO
+
+        # download from custom location
+        # TODO
+
+        # download from given url address
+        if ([ -n $url ] && ([ ! -s $cache_dir/$file ] || [ $force == $result_pos ])); then
+            # try to download
+            wget --tries=1 --connect-timeout=10 $url -O $file
+            # cache file
+            if [ -s $file ]; then
+                mv -f $file $cache_dir
+            fi
+        fi
+
+        # copy file to the download directory
+        if [ -s $cache_dir/$file ] && [ $cache_dir != $download_dir ]; then
+            cp -f $cache_dir/$file $download_dir
+        fi
+
+        # do not cache
+        if [ $do_not_cache == $result_pos ]; then
+            rm -f $cache_dir/$file
+        fi
+
+    fi
+
+    # check file size
+    if [ $expected_size -ne 0 ] && [ -s $download_dir/$file ]; then
+        local size=$(ls -l $download_dir/$file | awk '{ print $5 }')
+        if [ $expected_size -gt $size ]; then
+            rm -f $download_dir/$file
+        fi
+    fi
+
+    # return value
+    if [ -s $download_dir/$file ]; then
+        # check file hash
+        if [ -n "$expected_hash" ]; then
+            file_valid_hash $download_dir/$file $expected_hash $hash_algorithm
+        else
+            echo $result_pos
+        fi
+    else
+        echo $result_neg
+    fi
+
+    cd $current_dir
+}
+
+function file_valid_hash() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Validate hash sum of given file.
+
+    PARAMETERS:
+        \$1 file name
+        \$2 hash sum
+        \$3 algorithm (optional) md5,sha1,sha256,sha384,sha512 (default md5)
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local file=$1
+    local hash=$2
+    local algorithm=$3
+
+    [ -z "$algorithm" ] && algorithm="md5"
+    local current_hash=$(${algorithm}sum $file | awk '{ print $1 }')
+
+    if [ "$(lower $hash)" == "$(lower $current_hash)" ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function dir_find_str() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Search directory for files that contain given string.
+
+    PARAMETERS:
+        \$1 string to search for
+        \$2 directory (optional)
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local dir=$2
+
+    if [ "$dir" == "" ]; then
+        find . -iname "*" | xargs grep -iR "$str" | \
+            sort | uniq
+    else
+        find $dir -iname "*" | xargs grep -iR "$str" | \
+            sort | uniq
+    fi
+}
+
+function dir_replace_str() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Replace string in files in the given directory.
+
+    PARAMETERS:
+        \$1 string
+        \$2 new string
+        \$3 directory (optional)
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str1=$1
+    local str2=$2
+    local dir=$3
+    [ "$dir" == "" ] && dir=.
+
+    for file in $(find $dir -type f -name "*"); do
+        file_replace_str "$str1" "$str2" $file
+    done
+}
+
+function dir_remove_str() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Remove string in files in the given directory.
+
+    PARAMETERS:
+        \$1 string
+        \$2 directory (optional)
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local str=$1
+    local dir=$2
+    [ "$dir" == "" ] && dir=.
+
+    for file in $(find $dir -type f -name "*"); do
+        file_remove_str $str $file
+    done
+}
+
+################################################################################
+## chroot routines
+##
+
+function chroot_dependency_list() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: List dependencies of an executable file.
+
+    PARAMETERS:
+        \$1 executable file
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local bin=$1
+
+    (
+        local output=$(ldd $bin)
+        for line in $output; do
+            echo $line
+        done
+    ) 2> /dev/null | grep "^/" | sort | uniq
+}
+
+function chroot_dependency_list_all() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: List dependencies of an executable file recursively.
+
+    PARAMETERS:
+        \$1 executable file
+        --cur-depth <level> current depth of recursion (1 by default)
+        --max-depth <level> maximum depth of recursion (3 by default)
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local bin=$1
+
+    # get optional parameters
+    local cur_depth=1
+    local max_depth=3
+    while [ "$1" != "" ]; do
+        case $1 in
+            --cur-depth)    shift; cur_depth=$1
+                            ;;
+            --max-depth)    shift; max_depth=$1
+                            ;;
+        esac
+        shift
+    done
+
+    (
+        local output=$(chroot_dependency_list $bin)
+        for file in $output; do
+            echo "$file"
+            if [ $cur_depth -lt $max_depth ]; then
+                chroot_dependency_list_all $file --cur-depth $(expr $cur_depth + 1) --max-depth $max_depth
+            fi
+        done
+    ) 2> /dev/null | grep "^/" | sort | uniq
+}
+
+function chroot_dependency_copy() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Copy dependencies of an executable file recursively to chroot directory.
+
+    PARAMETERS:
+        \$1 executable file
+        \$2 chroot directory
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local bin=$1
+    local dir=$2
+
+    local output=$(chroot_dependency_list_all $bin)
+    for file in $output; do
+        echo "$file"
+        mkdir -p $dir/$(dirname $file)
+        cp $file $dir/$(dirname $file)
+    done
+}
+
+function chroot_mount_dir() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Mount directory in chroot environment.
+
+    PARAMETERS:
+        \$1 directory to mount
+        \$2 directory within chroot directory environment
+        --read-only
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local dir=$1
+    local chdir=$2
+    local read_only="n"
+    while [ "$1" != "" ]; do
+        case $1 in
+            --read-only)    read_only="y"
+                            ;;
+        esac
+        shift
+    done
+
+    if [ -d $dir ]; then
+        if [ "$(mount -l | grep $chdir | wc -l)" -gt 0 ]; then
+            umount $chdir
+        fi
+        mkdir -p $chdir
+        mount --bind $dir $chdir
+        if [ $read_only == "y" ]; then
+            mount -o remount,ro $chdir 2> /dev/null
+        fi
+    fi
+}
+
+function chroot_create_env() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Create chroot environment.
+
+    PARAMETERS:
+        \$1 chroot directory
+        --user <user> user name to mount their home directory
+        --home-read-only whether user home directory should be mounted as read-only
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local dir=$1
+
+    # get additional parameters
+    local user=
+    local home_read_only=
+    while [ "$1" != "" ]; do
+        case $1 in
+            --user)             shift; user=$1
+                                ;;
+            --home-read-only)   home_read_only="--read-only"
+                                ;;
+        esac
+        shift
+    done
+
+    [ ! -d $dir ] && mkdir $dir
+    mkdir -p $dir/{bin,dev/pts,etc,home,lib,lib64,proc,root,sbin,tmp,usr/bin,usr/include,usr/lib,usr/lib64,usr/sbin}
+
+    chmod 1777 $dir/tmp
+
+    # /bin
+    chroot_mount_dir /bin $dir/bin --read-only
+    # /dev/pts
+    chroot_mount_dir /dev/pts $dir/dev/pts
+    # /etc
+    chroot_mount_dir /etc $dir/etc --read-only
+    # /lib
+    chroot_mount_dir /lib $dir/lib --read-only
+    # /lib64
+    chroot_mount_dir /lib64 $dir/lib64 --read-only
+    # /proc
+    chroot_mount_dir /proc $dir/proc
+    # /sbin
+    chroot_mount_dir /sbin $dir/sbin --read-only
+    # /usr/bin
+    chroot_mount_dir /usr/bin $dir/usr/bin --read-only
+    # /usr/include
+    chroot_mount_dir /usr/include $dir/usr/include --read-only
+    # /usr/lib
+    chroot_mount_dir /usr/lib $dir/usr/lib --read-only
+    # /usr/lib64
+    chroot_mount_dir /usr/lib64 $dir/usr/lib64 --read-only
+    # /usr/sbin
+    chroot_mount_dir /usr/sbin $dir/usr/sbin --read-only
+
+    rm -f $dir/dev/null
+    mknod -m 666 $dir/dev/null c 1 3
+    rm -f $dir/dev/zero
+    mknod -m 666 $dir/dev/zero c 1 5
+    rm -f $dir/dev/random
+    mknod -m 444 $dir/dev/random c 1 8
+    rm -f $dir/dev/urandom
+    mknod -m 444 $dir/dev/urandom c 1 9
+
+    # user home directory
+    if [ -n "$user" ]; then
+        local home_dir=/home/$user
+        if [ "$user" == "root" ]; then
+            home_dir=/root
+        fi
+        if [ -d $home_dir ]; then
+            chroot_mount_dir $home_dir ${dir}${home_dir} $home_read_only
+        fi
+    fi
+}
+
+function chroot_remove_env() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Remove chroot environment.
+
+    PARAMETERS:
+        \$1 chroot directory
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local dir=$1
+
+    rm -f $dir/dev/null
+    rm -f $dir/dev/zero
+    rm -f $dir/dev/random
+    rm -f $dir/dev/urandom
+
+    for path in $(mount -l | grep $dir | awk '{ print $3 }'); do
+        umount $path
+    done
+
+    rm -rf $dir/tmp/*
+}
+
+function is_chroot() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Indicates if current environment is a chroot environment.
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    if [ $(stat -c %i /) != 2 ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+################################################################################
+## user routines
+##
+
+function user_exists() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if user exists.
+
+    PARAMETERS:
+        \$1 user
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local user=$1
+
+    if [ $(grep "^$1:" /etc/passwd | wc -l) == "1" ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function group_exists() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Check if group exists.
+
+    PARAMETERS:
+        \$1 group
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local group=$1
+
+    if [ $(grep "^$group:" /etc/group | wc -l) == "1" ]; then
+        echo $result_pos
+    else
+        echo $result_neg
+    fi
+}
+
+function user_create() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Create a new system user.
+
+    PARAMETERS:
+        \$1 user
+        \$2 group
+        --uid <user id>
+        --gid <group id>
+        --groups <list of groups>
+        --home <home directory>
+        --shell <shell>
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 2 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local user=$1
+    local group=$2
+
+    # get optional parameters
+    local uid="-K UID_MIN=${uid_min} -K UID_MAX=${uid_max}"
+    local gid="-K GID_MIN=${gid_min} -K GID_MAX=${gid_max}"
+    local groups=
+    local home="-d /dev/null"
+    local shell="-s /usr/sbin/nologin"
+    while [ "$1" != "" ]; do
+        case $1 in
+            --uid)      shift; uid="-u ${1}"
+                        ;;
+            --gid)      shift; gid="-g ${1}"
+                        ;;
+            --groups)   shift; groups="-G ${1}"
+                        ;;
+            --home)     shift; home="-d ${1}"
+                        ;;
+            --shell)    shift; shell="-s ${1}"
+                        ;;
+        esac
+        shift
+    done
+
+    groupadd $group $gid
+    useradd $user $uid -g $group $groups $home $shell
+}
+
+function user_delete() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Delete an existing system user.
+
+    PARAMETERS:
+        \$1 user
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -ne 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local user=$1
+
+    userdel -f $user > /dev/null 2>&1
+}
+
+################################################################################
+## security routines
+##
+
+function security_gen_cert() {
+
+    # define help
+    local help=$(cat <<HEREDOC
+
+    DESCRIPTION: Generates X.509 certificate.
+
+    PARAMETERS:
+        \$1 certificate name
+        --size <size> size of certificate (default is 2048)
+        --days <days> for how many days certificate remains valid (default is 3650)
+        --dir <dirctory> output dirctory
+HEREDOC
+)
+
+    # check parameters
+    if [ "$1" == "--help" ] || [ $# -lt 1 ]; then
+        echo -e "${help}\n"
+        return
+    fi
+
+    # get parameters
+    local name=$1
+    local size=2048
+    local days=3650
+    local dir=.
+    while [ "$1" != "" ]; do
+        case $1 in
+            --size) shift; size=$1
+                    ;;
+            --days) shift; days=$1
+                    ;;
+            --dir)  shift; dir=$1
+                    ;;
+        esac
+        shift
+    done
+
+    $cmd_openssl req \
+        -new -x509 -nodes -sha1 -newkey rsa:$size -days $days -subj "/O=unknown/OU=unknown/CN=$name" \
+        -keyout $dir/$name.key \
+        -out $dir/$name.crt
+    cat $dir/$name.crt $dir/$name.key > $dir/$name.pem
+    chmod 400 $dir/$name.{crt,key,pem}
+}
diff --git a/test/helper.rb b/test/helper.rb
new file mode 100644
index 00000000..780819dc
--- /dev/null
+++ b/test/helper.rb
@@ -0,0 +1,4 @@
+require "bundler/setup"
+require "test/unit"
+require "mocha/setup"
+require "linguist"
diff --git a/test/test_blob.rb b/test/test_blob.rb
index eb758534..4fe6b152 100644
--- a/test/test_blob.rb
+++ b/test/test_blob.rb
@@ -1,9 +1,4 @@
-require 'linguist/file_blob'
-require 'linguist/samples'
-
-require 'test/unit'
-require 'mocha/setup'
-require 'mime/types'
+require_relative "./helper"
 
 class TestBlob < Test::Unit::TestCase
   include Linguist
@@ -470,6 +465,25 @@ class TestBlob < Test::Unit::TestCase
       assert blob.language, "No language for #{sample[:path]}"
       assert_equal sample[:language], blob.language.name, blob.name
     end
+
+    # Test language detection for files which shouldn't be used as samples
+    root = File.expand_path('../fixtures', __FILE__)
+    Dir.entries(root).each do |language|
+      next unless File.file?(language)
+
+      # Each directory contains test files of a language
+      dirname = File.join(root, language)
+      Dir.entries(dirname).each do |filename|
+        next unless File.file?(filename)
+        
+        # By default blob search the file in the samples;
+        # thus, we need to give it the absolute path
+        filepath = File.join(dirname, filename)
+        blob = blob(filepath)
+        assert blob.language, "No language for #{filepath}"
+        assert_equal language, blob.language.name, blob.name
+      end
+    end
   end
 
   def test_minified_files_not_safe_to_highlight
diff --git a/test/test_classifier.rb b/test/test_classifier.rb
index 87c6feb2..8e1d8355 100644
--- a/test/test_classifier.rb
+++ b/test/test_classifier.rb
@@ -1,9 +1,4 @@
-require 'linguist/classifier'
-require 'linguist/language'
-require 'linguist/samples'
-require 'linguist/tokenizer'
-
-require 'test/unit'
+require_relative "./helper"
 
 class TestClassifier < Test::Unit::TestCase
   include Linguist
diff --git a/test/test_file_blob.rb b/test/test_file_blob.rb
new file mode 100644
index 00000000..9371dce7
--- /dev/null
+++ b/test/test_file_blob.rb
@@ -0,0 +1,10 @@
+require 'linguist/file_blob'
+require 'test/unit'
+
+class TestFileBlob < Test::Unit::TestCase
+  def test_extensions
+    assert_equal [".gitignore"], Linguist::FileBlob.new(".gitignore").extensions
+    assert_equal [".xml"],  Linguist::FileBlob.new("build.xml").extensions
+    assert_equal [".html.erb", ".erb"],  Linguist::FileBlob.new("dotted.dir/index.html.erb").extensions
+  end
+end
diff --git a/test/test_heuristics.rb b/test/test_heuristics.rb
index db8f286e..40713ca7 100644
--- a/test/test_heuristics.rb
+++ b/test/test_heuristics.rb
@@ -1,9 +1,4 @@
-require 'linguist/heuristics'
-require 'linguist/language'
-require 'linguist/samples'
-require 'linguist/file_blob'
-
-require 'test/unit'
+require_relative "./helper"
 
 class TestHeuristcs < Test::Unit::TestCase
   include Linguist
diff --git a/test/test_language.rb b/test/test_language.rb
index 1ad47e33..c5c5255f 100644
--- a/test/test_language.rb
+++ b/test/test_language.rb
@@ -1,6 +1,4 @@
-require 'linguist/language'
-require 'test/unit'
-require 'yaml'
+require_relative "./helper"
 
 class TestLanguage < Test::Unit::TestCase
   include Linguist
diff --git a/test/test_md5.rb b/test/test_md5.rb
index 6019fcf5..17006e2e 100644
--- a/test/test_md5.rb
+++ b/test/test_md5.rb
@@ -1,6 +1,4 @@
-require 'linguist/md5'
-
-require 'test/unit'
+require_relative "./helper"
 
 class TestMD5 < Test::Unit::TestCase
   include Linguist
diff --git a/test/test_pedantic.rb b/test/test_pedantic.rb
index c1819fb6..be8ce063 100644
--- a/test/test_pedantic.rb
+++ b/test/test_pedantic.rb
@@ -1,5 +1,4 @@
-require 'test/unit'
-require 'yaml'
+require_relative "./helper"
 
 class TestPedantic < Test::Unit::TestCase
   filename = File.expand_path("../../lib/linguist/languages.yml", __FILE__)
diff --git a/test/test_repository.rb b/test/test_repository.rb
index 1fba9b57..d07d86da 100644
--- a/test/test_repository.rb
+++ b/test/test_repository.rb
@@ -1,6 +1,4 @@
-require 'linguist/repository'
-require 'linguist/lazy_blob'
-require 'test/unit'
+require_relative "./helper"
 
 class TestRepository < Test::Unit::TestCase
   def rugged_repository
diff --git a/test/test_samples.rb b/test/test_samples.rb
index 929a7a00..06ede379 100644
--- a/test/test_samples.rb
+++ b/test/test_samples.rb
@@ -1,8 +1,5 @@
-require 'linguist/samples'
-require 'linguist/language'
-require 'tempfile'
-require 'yajl'
-require 'test/unit'
+require_relative "./helper"
+require "tempfile"
 
 class TestSamples < Test::Unit::TestCase
   include Linguist
@@ -34,23 +31,29 @@ class TestSamples < Test::Unit::TestCase
     assert_equal data['languages_total'], data['languages'].inject(0) { |n, (_, c)| n += c }
     assert_equal data['tokens_total'], data['language_tokens'].inject(0) { |n, (_, c)| n += c }
     assert_equal data['tokens_total'], data['tokens'].inject(0) { |n, (_, ts)| n += ts.inject(0) { |m, (_, c)| m += c } }
+    assert !data["interpreters"].empty?
   end
 
-  # Check that there aren't samples with extensions that aren't explicitly defined in languages.yml
-  def test_parity
-    extensions = Samples.cache['extnames']
-    languages_yml = File.expand_path("../../lib/linguist/languages.yml", __FILE__)
-    languages = YAML.load_file(languages_yml)
-
-    languages.each do |name, options|
+  # Check that there aren't samples with extensions or interpreters that
+  # aren't explicitly defined in languages.yml
+  languages_yml = File.expand_path("../../lib/linguist/languages.yml", __FILE__)
+  YAML.load_file(languages_yml).each do |name, options|
+    define_method "test_samples_have_parity_with_languages_yml_for_#{name}" do
       options['extensions'] ||= []
-
-      if extnames = extensions[name]
+      if extnames = Samples.cache['extnames'][name]
         extnames.each do |extname|
           next if extname == '.script!'
           assert options['extensions'].include?(extname), "#{name} has a sample with extension (#{extname}) that isn't explicitly defined in languages.yml"
         end
       end
+
+      options['interpreters'] ||= []
+      if interpreters = Samples.cache['interpreters'][name]
+        interpreters.each do |interpreter|
+          # next if extname == '.script!'
+          assert options['interpreters'].include?(interpreter), "#{name} has a sample with an interpreter (#{interpreter}) that isn't explicitly defined in languages.yml"
+        end
+      end
     end
   end
 
@@ -79,4 +82,9 @@ class TestSamples < Test::Unit::TestCase
       end
     end
   end
+
+  def test_shebang
+    assert_equal "crystal", Linguist.interpreter_from_shebang("#!/usr/bin/env bin/crystal")
+    assert_equal "python2", Linguist.interpreter_from_shebang("#!/usr/bin/python2.4")
+  end
 end
diff --git a/test/test_tokenizer.rb b/test/test_tokenizer.rb
index 0521f4da..5dab023e 100644
--- a/test/test_tokenizer.rb
+++ b/test/test_tokenizer.rb
@@ -1,6 +1,4 @@
-require 'linguist/tokenizer'
-
-require 'test/unit'
+require_relative "./helper"
 
 class TestTokenizer < Test::Unit::TestCase
   include Linguist
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deleted file mode 100644
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