Re: config files substitution with awk

[Ralf Wildenhues]

* Karl Berry wrote on Tue, Dec 05, 2006 at 12:14:28AM CET:
> 
> But for purposes of explaining to rms, can someone tell me (as briefly
> as possible :) why it is desirable to switch to awk instead of sticking
> with sed?
> 
> (I can imagine some reasons, but best to ask, I figure.)

The primary reason for introducing it to Autoconf was, that it allows a
faster substitution of variables.  Roughly speaking, a sed script like
   s/@var1@/text1/g
   s/@var2@/text2/g
   ...

used on an input file of the form
  address@hidden@
  address@hidden@
  ...

has an overhead scaling quadratically in the number of variables.
The original proposal has more details and measurements:
http://lists.gnu.org/archive/html/autoconf-patches/2006-11/msg00035.html


FWIW, I am working on a larger change to the list of makefile and
installation utilities in standards.texi.  If you want to wait, I
can try to finish it this weekend.

Cheers,
Ralf