Re: PCRE mode for sed

[Christoph Anton Mitterer]

Hi Bob.

On Mon, 2012-11-05 at 15:11 -0700, Bob Proulx wrote:
> For example the pcre
> library on my system and I am sure many others lives in the
> /usr/lib tree.  But that isn't available during early boot time
> before /usr has been assured of being mounted.  This caused various
> gratuitous bootstrapping problems.  The same problems will be there
> for sed.
Well...
a) at least in Debian (where grep is compiled --with-pcre) all seems to
work..
Haven't checked right now, what they do (static linking) or dlopen and
just forbid the use of -P in early stages.

b) The /usr/lib, /lib is not so unlikely to go away anyway,...
At least under Linux or systems that have some initramfs-like concept
one should be able to expect that /usr is there after boot... so all
you'd need is to put any libs into the early boot-areas (e.g. Linux'
initramfs) which can even be automated.

But even if not,... any OS is free to choose then whether to compile sed
with PCRE or not.


> One of the very strong
> advantages of sed is that it is standard.
True, but when someone wants to have guaranteed functionality, he
mustn't use anything beyond what POSIX specifies for sed (and it does
not give a PCRE mode ;) ).
If someone uses such fancy stuff he cannot complain afterwards about
portability issues.



Cheers,
Chris.

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