add tty

Makefile

@@ -6,7 +6,7 @@ LIB = util/afgets.o util/agetcwd.o util/concat.o util/enmasse.o util/eprintf.o \
 
 SRC = basename.c cat.c chmod.c chown.c date.c dirname.c echo.c false.c grep.c \
       head.c ln.c ls.c mkdir.c mkfifo.c nl.c pwd.c rm.c sleep.c sort.c tail.c \
-      tee.c touch.c true.c uname.c wc.c
+      tee.c touch.c true.c tty.c uname.c wc.c
 OBJ = $(SRC:.c=.o) $(LIB)
 BIN = $(SRC:.c=)
 MAN = $(SRC:.c=.1)

tty.1

@@ -0,0 +1,13 @@
+.TH TTY 1 sbase\-VERSION
+.SH NAME
+tty \- print terminal name
+.SH SYNOPSIS
+.B tty
+.SH DESCRIPTION
+.B tty
+prints the name of the terminal open on stdin.
+.P
+The status code is 0 if stdin is a terminal, and 1 if not.  If an error occurred
+the status code is 2.
+.SH SEE ALSO
+.IR ttyname (3)

tty.c

@@ -0,0 +1,24 @@
+/* See LICENSE file for copyright and license details. */
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+main(void)
+{
+	char *tty;
+
+	if((tty = ttyname(STDIN_FILENO))) {
+		puts(tty);
+		return 0;
+	}
+	else if(errno == ENOTTY) {
+		puts("not a tty");
+		return 1;
+	}
+	else {
+		perror("ttyname");
+		return 2;
+	}
+}

uname.c

@@ -41,7 +41,7 @@ main(int argc, char *argv[])
 			exit(EXIT_FAILURE);
 		}
 	if(uname(&u) == -1)
-		eprintf("uname failed:");
+		eprintf("uname:");
 
 	if(sflag || !(nflag || rflag || vflag || mflag))
 		printf("%s ", u.sysname);