--- ispell-3.1.20.orig/ispell.c

+++ ispell-3.1.20/ispell.c

@@ -256,6 +256,7 @@

     static char	outbuf[BUFSIZ];

     int		argno;

     int		arglen;

+    int		bflag = 0;

     int		dictdeft = 0;

     Cmd = *argv;

@@ -552,12 +553,13 @@

 		nodictflag++;

 		break;

 	    case 'b':

-		if (arglen > 2)

+		if (arglen > 2 || xflag == 1)

 		    usage ();

 		xflag = 0;		/* Keep a backup file */

+		bflag = 1;

 		break;

 	    case 'x':

-		if (arglen > 2)

+		if (arglen > 2 || bflag == 1)

 		    usage ();

 		xflag = 1;		/* Don't keep a backup file */

 		break;