Re: gnu shellery

[coypu%sdf.org@localhost]

adjusted per comments from uwe, to match head (and gnu)
code copied matching head.


add options to tail:
-q (never print header of filename)
-v (always print header of filename)

same as head, same as gnu tail

add tac which is like tail -rq

Index: Makefile
===================================================================
RCS file: /cvsroot/src/usr.bin/tail/Makefile,v
retrieving revision 1.3
diff -u -r1.3 Makefile
--- Makefile	23 Nov 1994 07:41:55 -0000	1.3
+++ Makefile	1 Oct 2017 17:03:33 -0000
@@ -1,7 +1,8 @@
 #	$NetBSD: Makefile,v 1.3 1994/11/23 07:41:55 jtc Exp $
 #	@(#)Makefile	8.1 (Berkeley) 6/6/93
-
 PROG=	tail
 SRCS=	forward.c misc.c read.c reverse.c tail.c
 
+LINKS=	${BINDIR}/tail ${BINDIR}/tac
+
 .include <bsd.prog.mk>
Index: tail.1
===================================================================
RCS file: /cvsroot/src/usr.bin/tail/tail.1,v
retrieving revision 1.17
diff -u -r1.17 tail.1
--- tail.1	4 Jul 2017 07:04:50 -0000	1.17
+++ tail.1	1 Oct 2017 17:03:33 -0000
@@ -32,7 +32,7 @@
 .\"
 .\"	@(#)tail.1	8.1 (Berkeley) 6/6/93
 .\"
-.Dd June 15, 2014
+.Dd October 1, 2017
 .Dt TAIL 1
 .Os
 .Sh NAME
@@ -43,7 +43,7 @@
 .Oo
 .Fl f |
 .Fl F |
-.Fl r
+.Fl rqv
 .Oc
 .Oo
 .Fl b Ar number |
@@ -133,12 +133,17 @@
 option is to display all of the input.
 .El
 .Pp
-If more than a single file is specified, each file is preceded by a
+If more than a single file is specified, or the
+.Fl v
+option is used, each file is preceded by a
 header consisting of the string
 .Dq ==> XXX \*[Le]=
 where
 .Dq XXX
 is the name of the file.
+The
+.Fl q
+flag disables the printing of the header in all cases.
 .Sh EXIT STATUS
 .Ex -std tail
 .Sh SEE ALSO
Index: tail.c
===================================================================
RCS file: /cvsroot/src/usr.bin/tail/tail.c,v
retrieving revision 1.17
diff -u -r1.17 tail.c
--- tail.c	31 Jan 2013 23:09:06 -0000	1.17
+++ tail.c	1 Oct 2017 17:03:33 -0000
@@ -67,6 +67,8 @@
 	enum STYLE style;
 	int ch, first;
 	char *p;
+	int qflag = 0;
+	int vflag = 0;
 
 	setprogname(argv[0]);
 	off = 0;
@@ -105,30 +107,45 @@
 
 	obsolete(argv);
 	style = NOTSET;
-	while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
-		switch(ch) {
-		case 'F':
-			fflag = 2;
-			break;
-		case 'b':
-			ARG(512, FBYTES, RBYTES);
-			break;
-		case 'c':
-			ARG(1, FBYTES, RBYTES);
-			break;
-		case 'f':
-			fflag = 1;
-			break;
-		case 'n':
-			ARG(1, FLINES, RLINES);
-			break;
-		case 'r':
-			rflag = 1;
-			break;
-		case '?':
-		default:
-			usage();
-		}
+	if (strcmp(getprogname(), "tail") == 0) {
+		while ((ch = getopt(argc, argv, "Fb:c:fn:rqv")) != -1)
+			switch(ch) {
+			case 'F':
+				fflag = 2;
+				break;
+			case 'b':
+				ARG(512, FBYTES, RBYTES);
+				break;
+			case 'c':
+				ARG(1, FBYTES, RBYTES);
+				break;
+			case 'f':
+				fflag = 1;
+				break;
+			case 'n':
+				ARG(1, FLINES, RLINES);
+				break;
+			case 'r':
+				rflag = 1;
+				break;
+			case 'q':
+				qflag = 1;
+				vflag = 0;
+				break;
+			case 'v':
+				qflag = 0;
+				vflag = 1;
+				break;
+			case '?':
+			default:
+				usage();
+			}
+	} else { /* tac */
+		qflag = 1;
+		vflag = 0;
+		rflag = 1;
+	}
+
 	argc -= optind;
 	argv += optind;
 
@@ -169,7 +186,7 @@
 				ierr();
 				continue;
 			}
-			if (argc > 1) {
+			if (vflag || (qflag == 0 && argc > 1)) {
 				(void)printf("%s==> %s <==\n",
 				    first ? "" : "\n", fname);
 				first = 0;
@@ -299,7 +316,7 @@
 usage(void)
 {
 	(void)fprintf(stderr,
-	    "Usage: %s [-f | -F | -r] [-b # | -c # | -n #] [file ...]\n",
+	    "Usage: %s [-f | -F | -rqv] [-b # | -c # | -n #] [file ...]\n",
 	    getprogname());
 	exit(1);
 }