open( my $FH, "<", \$content ) 
 or die "Kann File Handle nicht zum lesen aus content oeffnen";
.
.
$ftp->put( $FH, $remotefilename )
      or die "put failed (Passive=$passive) ", $ftp->message, "; localfilename(FH): [$localfilename], remotefilename: [$remotefilename]";
$ftp->quit;
                
close( $FH );