Re: A POSIX and a UTF-8 question

[Peter Stephenson <pws@csr.com>]

Daniel Qarras wrote:
> 1) There is unfortunately a bash-only expression used in RH's shell
> function library, that is =~. However, this was used only once in
> device mapper related function so that did not affect me, I just
> commented it out. YMMV. (I did not find a www description for this but
> it can be at least checked from bash3.1 manual pages what it does.

That's for extended regular expressions.  That wouldn't be too hard to
support, if we used the system's RE capabilities, although we'd probably
want to do parentheses differently.  However, as you say, it's specific
to bash so isn't that vital.

> 2) It seems that many RH scripts do something like:
> 
> cd /some/path
> . functions
> 
> and in zsh-4.3 as /bin/sh this does not work, it needs to be:
> 
> cd /some/path
> . ./functions

Right.  I think zsh has always been implemented like that.  We don't
really want to change it; the standard (IEEE Std 1003.1, 2004 Edition)
says specifically:

    RATIONALE

    Some older implementations searched the current directory for the
    file, even if the value of PATH disallowed it. This behavior was
    omitted from this volume of IEEE Std 1003.1-2001 due to concerns
    about introducing the susceptibility to trojan horses that the user
    might be trying to avoid by leaving dot out of PATH .

I checked on my Fedora system (about Core 4, I think) and the only init
script without a path is network:

  cd /etc/sysconfig/network-scripts

  . network-functions

If it's still there it probably ought to be fixed.

> Additionally, there's one cosmetic bash feature used that seems to be
> not supported by zsh: RH uses in their i18n effort tricks like:
>
> echo -n $"Starting service foo: "

It would be relatively easy to interpret these in the same fashion as
some other form of quoting.  However, there's not much
internationalization in these parts and won't be without a huge effort
and it's not clear it's worth the effort doing anything apart from that.

Thanks for the notes.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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