I think you're asking how to upload a file in CGI. If that's not your question, please just ignore me :)

Just create a multipart form with a file field:

<FORM METHOD=POST ACTION=/cgi-bin/upload.pl>
<INPUT TYPE=FILE NAME=UploadFile>
<INPUT TYPE=SUBMIT>
</FORM>
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And then read the file in your CGI:

use CGI;
my $q = new CGI;
my $filename = $q->param('UploadFile');
while (<$filename>) {
  # do something with each line of the file
}
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See the CGI manpage - search for "CREATING A FILE UPLOAD FIELD"

-- Dan