/* write0.c * *	purpose: send messages to another terminal *	 method: open the other terminal for output then *	 	 copy from stdin to that terminal *	  shows: a terminal is just a file supporting regular i/o *	  usage: write0 ttyname */#include	<stdio.h>#include	<fcntl.h>main( int ac, char *av[] ){	int	fd;	char	buf[BUFSIZ];	/* check args */	if ( ac != 2 ){		fprintf(stderr,"usage: write0 ttyname\n");		exit(1);	}	/* open devices */	fd = open( av[1], O_WRONLY );	if ( fd == -1 ){		perror(av[1]); exit(1);	}	/* loop until EOF on input */	while( fgets(buf, BUFSIZ, stdin) != NULL )		if ( write(fd, buf, strlen(buf)) == -1 )			break;	close( fd );}