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Re: grep --ignore-case efficiency
From: |
arnold |
Subject: |
Re: grep --ignore-case efficiency |
Date: |
Wed, 30 Jan 2013 00:09:41 -0700 |
User-agent: |
Heirloom mailx 12.4 7/29/08 |
Hello.
You do not state which version of grep you are using (grep --version will
tell you, and us). Older versions of grep did indeed have some issues
with ignoring case in non-ASCII locales. The simple solution was to do
export LC_ALL=C
and then run grep, which would give you a big speedup.
More recent versions of grep have had a lot of work done in this area.
You may wish to try downloading and building the most recent release
and then see if it runs faster.
HTH,
Arnold
Paulo Nogueira <address@hidden> wrote:
> Hello,
>
> this is not about a bug in the usual sense, rather
> about the poor(?) efficiency of "grep --ignore-case"
> as compared to the default do-not-ignore-case.
>
> Although I am completely oblivious of the inner workings
> of grep, it seems rather strange that the ignore-case
> could take (say) tens of times longer to execute than
> the do-not-ignore-case -- and I am referring to normal
> ASCII files.
>
> Provided there is an efficient way to convert from one
> character case to the other, as there is in ASCII (say)
> it seems pretty obvious that one could achieve a much
> smaller execution-time ratio. Is the need to accommodate
> for a generic character set the problem? What is?
>
> Best regards
> Paulo