Hello! :)

You can use pipes | to send a program output to (another) program input.
For example to send an attach with sendmail via CGI, without using a temporary file to mimencode the attach, you can pipe the output from cat to the input of mimencode:

        #code from a sub
        unless (open(MAIL, "| $sendmail ")) {
                return 0
        };

        my $attach=$q->param('upfile');
        my $path = $q->tmpFileName($attach);
        open (ATTACH,"cat $path | mimencode |") or return 0;

        [cut]

        close ATTACH;
        close MAIL;
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