Make ed's 'l' command end lines with a '$' and make sure that literal

'$' characters are escaped, so that we are POSIX compliant.

The omission of trailing '$' was originally hidden behind a BACKWARDS
flag. This flag was most likely introduced to be compatible with 4.4BSD.
Thanks to naddy@ for pointing me to the 4.4BSD ed implementation.

I tried to trace the origin and enabling of the BACKWARDS flag, since
both FreeBSD and NetBSD have the flag, but only FreeBSD doesn't have it
enabled. Both projects had an alm@ working on ed during 1993-1995 during
which he added this flag to both projects and only enabled it on NetBSD,
but I wasn't able to reach him on any known address.
Thanks to Ed Schouten (ed@freebsd), and Michael W. Lucas of the ed
Mastery book for helping me trying to locate Andrew Moore.

Problem originally prodded by garzon.lucero@gmail.com and later
independently re-requested by n.reusse@hxgn.net.

OK tb@, guenther@, and mwl@mwl.io

2 files changed, 6 insertions, 21 deletions

diff --git a/bin/ed/ed.1 b/bin/ed/ed.1
index 8359cf292fa..aefb0d59d12 100644
--- a/bin/ed/ed.1
+++ b/bin/ed/ed.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ed.1,v 1.69 2017/07/05 12:23:46 schwarze Exp $
+.\"	$OpenBSD: ed.1,v 1.70 2018/04/26 12:18:54 martijn Exp $
 .\"
 .\" Copyright (c) 1993 Andrew Moore, Talke Studio.
 .\" All rights reserved.
@@ -24,7 +24,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: July 5 2017 $
+.Dd $Mdocdate: April 26 2018 $
 .Dt ED 1
 .Os
 .Sh NAME
@@ -807,19 +807,6 @@ additionally, it says behaviour for the
 .Fl
 option is
 .Dq unspecified .
-.Pp
-The
-.St -p1003.1-2008
-specification says the
-.Ic l
-command should mark the ends of lines with a
-.Sq $
-character,
-and that
-.Sq $
-characters
-within the text should be output preceded by a backslash;
-this implementation does not support that.
 .Sh HISTORY
 An
 .Nm
diff --git a/bin/ed/io.c b/bin/ed/io.c
index 13e2c583b8d..de2f2586b36 100644
--- a/bin/ed/io.c
+++ b/bin/ed/io.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: io.c,v 1.20 2017/04/26 21:25:43 naddy Exp $	*/
+/*	$OpenBSD: io.c,v 1.21 2018/04/26 12:18:54 martijn Exp $	*/
 /*	$NetBSD: io.c,v 1.2 1995/03/21 09:04:43 cgd Exp $	*/
 
 /* io.c: This file contains the i/o routines for the ed line editor */
@@ -295,8 +295,8 @@ get_tty_line(void)
 
 
 
-#define ESCAPES "\a\b\f\n\r\t\v\\"
-#define ESCCHARS "abfnrtv\\"
+#define ESCAPES "\a\b\f\n\r\t\v\\$"
+#define ESCCHARS "abfnrtv\\$"
 
 extern int rows;
 extern int cols;
@@ -330,7 +330,7 @@ put_tty_line(char *s, int l, int n, int gflag)
 #endif
 		}
 		if (gflag & GLS) {
-			if (31 < *s && *s < 127 && *s != '\\')
+			if (31 < *s && *s < 127 && *s != '\\' && *s != '$')
 				putchar(*s);
 			else {
 				putchar('\\');
@@ -348,10 +348,8 @@ put_tty_line(char *s, int l, int n, int gflag)
 		} else
 			putchar(*s);
 	}
-#ifndef BACKWARDS
 	if (gflag & GLS)
 		putchar('$');
-#endif
 	putchar('\n');
 	return 0;
 }