Simplify shebang detection

lib/linguist/shebang.rb

@@ -5,27 +5,17 @@ module Linguist
       Language.find_by_interpreter(new(blob.data).interpreter)
     end
 
-    attr_reader :data
-
     def initialize(data)
-      @data = data
+      @lines = data.lines
     end
 
     def interpreter
-      lines = data.lines.to_a
+      return unless match = /^#! ?(.*)$/.match(@lines.first)
 
-      if lines.any? && (match = lines[0].match(/(.+)\n?/)) && (bang = match[0]) =~ /^#!/
-        bang.sub!(/^#! /, '#!')
-        tokens = bang.split(' ')
-        pieces = tokens.first.split('/')
+      tokens = match[0].split(' ')
+      script = tokens.first.split('/').last
 
-        if pieces.size > 1
-          script = pieces.last
-        else
-          script = pieces.first.sub('#!', '')
-        end
-
-        script = script == 'env' ? tokens[1] : script
+      script = tokens[1] if script == 'env'
 
       # If script has an invalid shebang, we might get here
       return unless script
@@ -35,15 +25,11 @@ module Linguist
 
       # Check for multiline shebang hacks that call `exec`
       if script == 'sh' &&
-          lines[0...5].any? { |l| l.match(/exec (\w+).+\$0.+\$@/) }
+        @lines[0...5].any? { |l| l.match(/exec (\w+).+\$0.+\$@/) }
         script = $1
       end
 
       File.basename(script)
-      else
-        nil
-      end
-
     end
   end
 end