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#include <u.h>
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#include <libc.h>
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int	multi;
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int	nlines;
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char	*status = nil;
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int
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line(int fd, char *file)
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{
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	char c;
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	int m, n, nalloc;
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	char *buf;
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	nalloc = 0;
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	buf = nil;
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	for(m=0; ; ){
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		n = read(fd, &c, 1);
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		if(n < 0){
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			fprint(2, "read: error reading %s: %r\n", file);
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			exits("read error");
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		}
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		if(n == 0){
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			if(m == 0)
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				status = "eof";
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			break;
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		}
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		if(m == nalloc){
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			nalloc += 1024;
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			buf = realloc(buf, nalloc);
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			if(buf == nil){
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				fprint(2, "read: malloc error: %r\n");
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				exits("malloc");
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			}
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		}
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		buf[m++] = c;
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		if(c == '\n')
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			break;
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	}
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	if(m > 0)
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		write(1, buf, m);
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	free(buf);
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	return m;
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}
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void
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lines(int fd, char *file)
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{
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	do{
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		if(line(fd, file) == 0)
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			break;
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	}while(multi || --nlines>0);
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}
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void
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main(int argc, char *argv[])
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{
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	int i, fd;
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	char *s;
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	ARGBEGIN{
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	case 'm':
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		multi = 1;
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		break;
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	case 'n':
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		s = ARGF();
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		if(s){
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			nlines = atoi(s);
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			break;
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		}
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		/* fall through */
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	default:
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		fprint(2, "usage: read [-m] [-n nlines] [files...]\n");
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		exits("usage");
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	}ARGEND
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	if(argc == 0)
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		lines(0, "<stdin>");
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	else
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		for(i=0; i<argc; i++){
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			fd = open(argv[i], OREAD);
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			if(fd < 0){
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				fprint(2, "read: can't open %s: %r\n", argv[i]);
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				exits("open");
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			}
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			lines(fd, argv[i]);
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			close(fd);
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		}
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	exits(status);
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}