# program to remove a leading UTF-8 BOM from a file
# works both STDIN -> STDOUT and on the spot (with filename as argument)

if ($#ARGV > 0) {
    print STDERR "Too many arguments!\n";
    exit;
}

my @file;   # file content
my $lineno = 0;

my $filename = @ARGV[0];
if ($filename) {
    	open( BOMFILE, $filename ) || die "Could not open source file for reading.";
	while (<BOMFILE>) {
		if ($lineno++ == 0) {
			if ( index( $_, '' ) == 0 ) {
				s/^\xEF\xBB\xBF//;
				print "BOM found and removed.\n";
				}
			else { print "No BOM found.\n"; }
        			}
        		push @file, $_ ;
    		}
    	close (BOMFILE)  || die "Can't close source file after reading.";

    	open (NOBOMFILE, ">$filename") || die "Could not open source file for writing.";
    	foreach $line (@file) {
       		print NOBOMFILE $line;
    		}
    	close (NOBOMFILE)  || die "Can't close source file after writing.";
	}
else {  # STDIN -> STDOUT
    	while (<>) {
        		if (!$lineno++) {
            			s/^\xEF\xBB\xBF//;
        			}
        		push @file, $_ ;
    		}
    	foreach $line (@file) {
        		print $line;
    		}
	}