in with the new

src/cmd/read.c

@@ -0,0 +1,91 @@
+#include <u.h>
+#include <libc.h>
+
+int	multi;
+int	nlines;
+char	*status = nil;
+
+int
+line(int fd, char *file)
+{
+	char c;
+	int m, n, nalloc;
+	char *buf;
+
+	nalloc = 0;
+	buf = nil;
+	for(m=0; ; ){
+		n = read(fd, &c, 1);
+		if(n < 0){
+			fprint(2, "read: error reading %s: %r\n", file);
+			exits("read error");
+		}
+		if(n == 0){
+			if(m == 0)
+				status = "eof";
+			break;
+		}
+		if(m == nalloc){
+			nalloc += 1024;
+			buf = realloc(buf, nalloc);
+			if(buf == nil){
+				fprint(2, "read: malloc error: %r\n");
+				exits("malloc");
+			}
+		}
+		buf[m++] = c;
+		if(c == '\n')
+			break;
+	}
+	if(m > 0)
+		write(1, buf, m);
+	free(buf);
+	return m;
+}
+
+void
+lines(int fd, char *file)
+{
+	do{
+		if(line(fd, file) == 0)
+			break;
+	}while(multi || --nlines>0);
+}
+
+void
+main(int argc, char *argv[])
+{
+	int i, fd;
+	char *s;
+
+	ARGBEGIN{
+	case 'm':
+		multi = 1;
+		break;
+	case 'n':
+		s = ARGF();
+		if(s){
+			nlines = atoi(s);
+			break;
+		}
+		/* fall through */
+	default:
+		fprint(2, "usage: read [-m] [-n nlines] [files...]\n");
+		exits("usage");
+	}ARGEND
+
+	if(argc == 0)
+		lines(0, "<stdin>");
+	else
+		for(i=0; i<argc; i++){
+			fd = open(argv[i], OREAD);
+			if(fd < 0){
+				fprint(2, "read: can't open %s: %r\n", argv[i]);
+				exits("open");
+			}
+			lines(fd, argv[i]);
+			close(fd);
+		}
+
+	exits(status);
+}