Re: M4sh tests 77 and 78 vs /bin/sh -> dash

[Bob Friesenhahn]

On Fri, 13 Mar 2020, Sébastien Hinderer wrote:
> Is the time spent in the shell such a big part of configure's total
> execution time?
>
> I am also wondering how widely config.status is known by non-experts. I
> guess in the situation where the time spent ocnfiguring matters, e.g.
> when you are developing, running ocnfig.status would be enough.

For developers, who need to configure over and over again, using 
configure's --config-cache option helps quite a lot.

The best way to see if a shell actually appears to work and the amount 
of time spent in configure is to do something like

env CONFIG_SHELL=/bin/dash ./configure

and see how its timing compares with /bin/bash, or some other shell.

Some shells such as Sun/Solaris legacy /bin/sh just plain don't work 
(but there are viable alternatives via other paths).

It is not clear if bash is any slower than other shells at executing 
algorithmic things like loops, but it was noticed to be slower at 
parsing large numbers of simple commands and Autoconf configure 
scripts are often almost 1MB of script.

Bob
--
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
Public Key,     http://www.simplesystems.org/users/bfriesen/public-key.txt