You need to open a file on that filehandle...

open(SEASAME,"file_to_send" or die $!;
$ftp->put( <SESAME> ,"ftptest");
close SEASAME;

#or more simply 
$ftp->put( "file_to_send", "name_to_put_as");
[download]

What you are doing doesn't really do much. To do what you are trying you would probably have to create a tied filehandle. For writing text to a remote file with Net::FTP look at the stor method of Net::FTP which lets you use write to put up data from a buffer.

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