A patch for Jay Painter and Stuart Parmenter's Balsa. When this patch is applied, a user may specify mail attachments on the command line using the -a or --attachment option.
Incidentally, this patch allows one to integrate Balsa very nicely with the graphical shell Nautilus. One can right click on selected files, scale them to a reasonable size, and open a new mail message with them attached if one places my mail_file script in their Nautilus scripts directory. Mail_file is distributed in my nautilus_scripts package.