4a5,6
>    
>    [small changes 2003 David Gümbel (david.guembel @ gmx.net)]
236,237c238,241
< 
< 	if(!(in = fopen(inf, "r"))) {
---
> 	
> 	/* read from stdin if "-" is given as source filename (DG) */
> 	if (strcmp(inf,"-") == 0) { in = stdin; }
> 	else if(!(in = fopen(inf, "r"))) {
241,242c245,247
< 
< 	if(!(out = fopen(outf, "w"))) {
---
> 	/* write to stdout if "-" is given as target filename (DG) */
> 	if (strcmp(outf,"-") == 0) { out = stdout; }
> 	else if(!(out = fopen(outf, "w"))) {