Make yaourt does not reinstall when already installed

A solution can be made with a simple script:

1. Open file

   $ vim yaourt-helper.sh
   

2. Create script

   #!/bin/bash
   _update="yaourt -Syua --noconfirm"
   if ! which $1 2>/dev/null 1>&2; then
      echo 'Package not installed, installing'
      $_update $1
      exit $?;
   fi
   echo 'Already installed, checking for upgrade'
   $_update
   

3. Set permissions and execute

$ chmod +x yaourt-helper.sh && ./yaourt-helper.sh jruby

Note: using --noconfirm is dangerous unless your know exactly what you're doing.