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Re: Possible eval builtin speedup?


From: Nicolas Bonifas
Subject: Re: Possible eval builtin speedup?
Date: Thu, 6 Mar 2008 21:56:15 +0100

>  > I don't know much about bash internals, but there is probably room for
>  > a huge performance improvement in speeding up the eval builtin.
>  > What do you think about it? Would it be a difficult task?
>
>     It is more likely to be the command substitution that is slow.

You're right:
$ time (echo `dircolors` > /dev/null)

real    0m0.318s
user    0m0.312s
sys     0m0.008s

I ran the previous tests with bash-3.1. With bash-3.2, echo
`dircolors` take 0.088s of user time (1/4th of the time needed by
bash-3.1), and dircolors > dircolors_output && sh ./dircolors_output
still takes 0.004s, so it is more than 20 times faster than using
command substitution.

So, do you think that speeding up command substitution would be a
difficult task?

Regards,
Nicolas




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