Switch with for via && and ||

• Be careful that the RHS of && is always true.

         $dir = 'http://www.wins.uva.nl/~mes/jargon';
         for ($ENV{HTTP_USER_AGENT}) {
         $page  =    /Mac/            && 'm/Macintrash.html'
                  || /Win(dows )?NT/  && 'e/evilandrude.html'
                  || /Win|MSIE|WebTV/ && 'm/MicroslothWindows.html'
                  || /Linux/          && 'l/Linux.html'
                  || /HP-UX/          && 'h/HP-SUX.html'
                  || /SunOS/          && 's/ScumOS.html'
                  ||                     'a/AppendixB.html';
         }