add directory study

study/linux-travel/MINIX-1.5/1.5/Source/commands/tty.c

@@ -0,0 +1,23 @@
+/* tty.c - Return tty name		Author: Freeman P. Pascal IV */
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+
+int main(argc, argv)
+int argc;
+char *argv[];
+{
+  char *tty_name;
+
+  tty_name = ttyname(0);
+  if ((argc == 2) && (!strcmp(argv[1], "-s")))
+	 /* Do nothing - shhh! we're in silent mode */ ;
+  else
+	puts((tty_name != (char *) NULL) ? tty_name : "Not a tty");
+
+  if (tty_name == (char *) NULL)
+	exit(1);
+  else
+	exit(0);
+}