`attach`

Here's the usage:

     /home/mjd/bin/attach -O [-f from] [-s subject] [-o outputfile] 
           [-m message body] [-t to] [attachments...]
       -o  deliver message to specified output file (-o"| command" OK)
           (default STDOUT)
       -O  inject message into mail system directly
       -f  specify 'from' address (default mjd@plover.com)
       -t  specify 'to' address (default none)
       -s  specify subject (default none)
       -m  specify input file for message body (-m"command |" OK)
           (default: read from stdin like /bin/mail)

-Q is an undocumented recent addition

It's short for -O -s "attached file" -m /dev/null:

        if ($opt_Q) {
          $opt_O = 1;
          $opt_s ||= "attached file";
          $opt_m ||= "/dev/null";
        }