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Re: sed --posix does not catch incomplete arguments

From: Ralf Wildenhues
Subject: Re: sed --posix does not catch incomplete arguments
Date: Tue, 22 Jun 2010 07:29:35 +0200
User-agent: Mutt/1.5.20 (2010-04-22)

[ moving from bug-autoconf ]

Hi Bruno, Eric,

* Bruno Haible wrote on Tue, Jun 22, 2010 at 01:42:20AM CEST:
> Ralf Wildenhues wrote:
> > > Here's what I see on Solaris 10:
> > > 
> > >   $ echo a | sed -n -e 'i\' -e 0
> > >   Unrecognized command: 0
> > 
> > JFTR, while i\ is a problem for some seds, I don't find any sed that
> > rejects
> >   sed -e 1{ -e }
> > 
> > among IRIX 6.5, AIX 5.1, Tru64 5.1D, BSDs, Solaris 2.6 or newer.
> > The problem seems to be relevant only for scripts ending trailing
> > backslash (which is far less often a problem in sed scripts).
> OK, feel free to change the wording that I submitted (doc/autoconf.texi around
> line 18244).

Here's a suggestion.


    Specify sed -e limitation in more detail.
    * doc/autoconf.texi (Limitations of Usual Tools): Document that
    splitting along sed command boundaries is portable in practice.

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index c2772fe..4dfde1d 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -18239,13 +18239,13 @@ Limitations of Usual Tools
 should use semicolon only with simple scripts that do not use these
-The argument of the @option{-e} option must be a syntactically complete
-script.  GNU @command{sed} allows to pass multiple script fragments,
-each as argument of a separate @option{-e} option, that are then combined,
-with newlines between the fragments.  A future Posix revision may allow
-this as well.  But in Posix:2008, this is not allowed, and the
address@hidden programs on Solaris 10, HP-UX 11, and AIX don't allow it
+Posix up to the 2008 revision requires the argument of the @option{-e}
+option to be a syntactically complete script.  GNU @command{sed} allows
+to pass multiple script fragments, each as argument of a separate
address@hidden option, that are then combined, with newlines between the
+fragments, and a future Posix revision may allow this as well.  For
+example, the @command{sed} programs on Solaris 10, HP-UX 11, and AIX
+don't allow splitting in this case:
 $ @kbd{echo a | sed -n -e 'i\}
@@ -18255,6 +18255,17 @@ Limitations of Usual Tools
 Unrecognized command: 0
 @end example
+In practice, however, it is portable to pass fragments to separate
address@hidden options that each represent full @command{sed} commands,
+even if that is not specified by Posix:
address@hidden The quote around the closing brace silences interactive zsh.
+$ @kbd{echo a | sed -n -e '/a/@{' -e s/a/b/ -e p -e '@}'}
address@hidden example
 Commands inside @{ @} brackets are further restricted.  Posix says that
 they cannot be preceded by addresses, @samp{!}, or @samp{;}, and that
 each command must be followed immediately by a newline, without any

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