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bug#14224: Feature request for the `cut`: record delimiter


From: Bob Proulx
Subject: bug#14224: Feature request for the `cut`: record delimiter
Date: Thu, 18 Apr 2013 12:56:21 -0600
User-agent: Mutt/1.5.21 (2010-09-15)

George Brink wrote:
> Actually I just found yet another way to solve my problem:
> perl -0002 -F"\001" -an -e "print((join \"\001\", @F[0..2,14..46]), 
> \"\002\");" data.dat >new_data.dat
> It works fine,

I was thinking of Perl's -0 option when I asked if you would say a few
words about the file and task.  But since you had described it yet I
was hesitant to suggest it.

> but I am a little concerned of the speed. I have over three
> hundreds of such files, from 3Mb to 30Mb each. And this process should be
> run every day... I thought that by using cut (which just looks for
> delimiters) I can gain a few minutes on the whole process.

I always recommend benchmarking before optimizing.  Knuth is quoted as
"We should forget about small efficiencies, say about 97% of the time:
premature optimization is the root of all evil".

Don't forget programmer productivity either.  You might shave 10% off
of something now but making it imcomprehensible to future admin
maintainers who need to understand it later.  Simply upgrading the
hardware might give a 50% increase in performance.  In which case I
would leave the algorithm simple and more easily understand and not
worry about the performance.  Simple and easy to understand is better
than raw speed.

> Bob,
> I understand your desire to receive a discussion of features not inside the
> bug related mail list, but here is a extract from the README:
> > Mail suggestions and bug reports for these programs to
> > the address on the last line of --help output.
> And guess what, the `cut --help` has the bug-coreutils email in the last
> line! The coreutils email is not mentioned inside README at all. And
> bug-coreutils is mentioned several times in different context.
> I apologize for using this mail-list inappropriately, but I did not know
> about any other mail-lists

As Pádraig said, no worries.  I didn't mean it to sound mean or
snarky.  But I can see that my last sentence did come out that way.
Sorry.

But if I didn't say anything then you wouldn't have said anything and
then we wouldn't have been reminded that the contact address hadn't
been updated in your version.  So it ended well.  The way to get the
word out is by continuing to talk about it.  If people even just read
it in passing then they might be informed for the future.

Bob





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