I am automating a process that will zip a folder using rar. When I use Winrar and choose to create a .ZIP archive manually through the GUI, the files are readable by my client. When I try to duplicate the process using rar from the command line (in effort to automate this process), even though I name my file with the .ZIP file extension, the files cannot be processed by my client's process. My client gets a message that says that the file is not a valid zip file. Is there a trick for creating an authentic .ZIP file using rar at the command line?