* Re: [Emacs-diffs] master 2534676 2/2: Simplify setfattr use by assuming GNU make
2015-01-02 19:12 ` [Emacs-diffs] master 2534676 2/2: Simplify setfattr use by assuming GNU make Glenn Morris
@ 2015-01-02 21:19 ` Paul Eggert
0 siblings, 0 replies; 2+ messages in thread
From: Paul Eggert @ 2015-01-02 21:19 UTC (permalink / raw)
To: Glenn Morris; +Cc: Autoconf patches, Emacs development discussions
[-- Attachment #1: Type: text/plain, Size: 393 bytes --]
On 01/02/2015 11:12 AM, Glenn Morris wrote:
> The autoconf manual says "Don't rely on ln having a -f option."
Although that was good advice in the early 1990s when that part of the
Autoconf manual was written, the advice has been obsolete for years. I
installed the attached patch into Autoconf to fix this (after bumping
Autoconf's copyright year). I'm CC:ing this to autoconf-patches.
[-- Attachment #2: 0001-doc-f-is-now-portable-for-cp-and-ln.patch --]
[-- Type: text/x-patch, Size: 1932 bytes --]
From 4774ff5c33d34bb6ad21c06f3c2b54d6e700740e Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 2 Jan 2015 13:02:48 -0800
Subject: [PATCH] doc: -f is now portable for cp and ln
This follows up on a comment by Glenn Morris in:
http://lists.gnu.org/archive/html/emacs-devel/2015-01/msg00011.html
* doc/autoconf.texi (Limitations of Usual Tools):
Remove circa-1990 advice about avoiding cp -f and ln -f.
Although that advice was reasonable for the early 1990s, the -f
option is portable for both cp and ln nowadays. These options
were standardized in POSIX 1003.2-1992, and pre-POSIX systems such
as SunOS 4 are no longer of practical concern.
---
doc/autoconf.texi | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 639cec2..d9e833d 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -18684,9 +18684,7 @@ avoid this problem, omit the trailing slashes. For example, use
@samp{cp -R source /tmp/newdir} rather than @samp{cp -R source
/tmp/newdir/} if @file{/tmp/newdir} does not exist.
-@c This is thanks to Ian.
-The ancient SunOS 4 @command{cp} does not support @option{-f}, although
-its @command{mv} does.
+The @option{-f} option is portable nowadays.
@cindex timestamp resolution
Traditionally, file timestamps had 1-second resolution, and @samp{cp
@@ -19088,9 +19086,11 @@ the workaround is to use @command{join -a1 file1 file2} instead.
@item @command{ln}
@c ---------------
@prindex @command{ln}
+The @option{-f} option is portable nowadays.
+
@cindex Symbolic links
-Don't rely on @command{ln} having a @option{-f} option. Symbolic links
-are not available on old systems; use @samp{$(LN_S)} as a portable substitute.
+Symbolic links are not available on some systems; use @samp{$(LN_S)} as
+a portable substitute.
For versions of the DJGPP before 2.04,
@command{ln} emulates symbolic links
--
2.1.0
^ permalink raw reply related [flat|nested] 2+ messages in thread