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Re: mention DUALCASE
From: |
Paul Eggert |
Subject: |
Re: mention DUALCASE |
Date: |
Wed, 02 Feb 2005 16:32:32 -0800 |
User-agent: |
Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (gnu/linux) |
Thanks for that suggestion. I installed the following more-general patch.
2005-02-02 Paul Eggert <address@hidden>
* doc/autoconf.texi (Special Shell Variables): Mention _,
BIN_SH, DUALCASE. Say that variables other than "status" are safe
if they contain a lower-case letter. The DUALCASE problem was
reported by Ralf Wildenhues.
Index: autoconf.texi
===================================================================
RCS file: /cvsroot/autoconf/autoconf/doc/autoconf.texi,v
retrieving revision 1.872
retrieving revision 1.873
diff -p -u -r1.872 -r1.873
--- autoconf.texi 2 Feb 2005 23:47:34 -0000 1.872
+++ autoconf.texi 3 Feb 2005 00:31:33 -0000 1.873
@@ -10405,10 +10405,31 @@ Some shell variables should not be used,
influence on the behavior of the shell. In order to recover a sane
behavior from the shell, some variables should be unset, but
@command{unset} is not portable (@pxref{Limitations of Builtins}) and a
-fallback value is needed. We list these values below.
+fallback value is needed.
+
+As a general rule, shell variable names containing a lower-case letter
+are safe; you can define and use these variables without worrying about
+their effect on the underlying system, and without worrying about
+whether the shell will change them unexpectedly. (The exception is the
+shell variable @code{status}, as described below.)
+
+Here is a list of names that are known to cause trouble. This list is
+not exhaustive, but you should be safe if you avoid the name
address@hidden and names containing only upper-case letters and
+underscores.
@c Alphabetical order, case insensitive, `A' before `a'.
@table @code
address@hidden _
+Many shells reserve @samp{$_} for various purposes, e.g., the name of
+the last command executed.
+
address@hidden BIN_SH
address@hidden BIN_SH
+In Tru64, if @env{BIN_SH} is set to @code{xpg4}, subsidiary invocations of
+the standard shell conform to Posix.
+Autoconf-generated scripts export this variable when they start up.
+
@item CDPATH
@evindex CDPATH
When this variable is set it specifies a list of directories to search
@@ -10431,6 +10452,12 @@ In practice the shells that have this pr
Autoconf-generated scripts automatically unset @code{CDPATH} if
possible, so you need not worry about this problem in those scripts.
address@hidden DUALCASE
address@hidden DUALCASE
+In the MKS shell, case statements and file name generation are
+case-insensitive unless @code{DUALCASE} is nonzero.
+Autoconf-generated scripts export this variable when they start up.
+
@item IFS
@evindex IFS
Don't set the first character of @code{IFS} to backslash. Indeed,
- mention DUALCASE, Ralf Wildenhues, 2005/02/01
- Re: mention DUALCASE,
Paul Eggert <=