posixutils

commit 7dc4efc1556ba34065a86035fdc3670732c977af
parent 6dad92f0fb8e6e46d524c40ae11afd85e7f2108a
Author: z3bra <willyatmailoodotorg>
Date:   Sun Apr 24 19:24:45 2016

cat.c: read from stdin for filename "-"

Diffstat:
 cat.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/cat.c b/cat.c
@@ -13,13 +13,23 @@ main(int argc, char **argv)
 	char buf[LINE_MAX];
 
 	while (*(++argv) != NULL) {
-		fd = open(*argv, O_RDONLY);
+
+		/* if filename is "-", read file from stdin */
+		if ((*argv)[0] == '-' && (*argv)[1] == 0) {
+			fd = 0;
+		/* else, open the filename given as argument */
+		} else {
+			fd = open(*argv, O_RDONLY);
+		}
+
 		if (fd < 0) {
 			perror(*argv);
 		} else {
+			/* read file in chunks, and write them to stdout */
 			while ((len = read(fd, buf, LINE_MAX)) > 0) {
 				write(1, buf, len);
 			}
+			/* gracefully close file descriptor */
 			close(fd);
 		}
 	}