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help / color / mirror / Atom feedFrom: Ron Johnson <[email protected]>
To: pgsql-general <[email protected]>
Subject: Re: Better way to process records in bash?
Date: Thu, 12 Sep 2024 15:43:59 -0400
Message-ID: <CANzqJaAJe-HhKGtfvJXtL1q=U6FsJ+-hcRh=Wvzy=MKyAvTzeQ@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CANzqJaCaLwc6rOK7O8PkCgVDi_8fg6duzdUrMy0rtn_tQL144g@mail.gmail.com>
<[email protected]>
On Thu, Sep 12, 2024 at 3:30 PM Christoph Moench-Tegeder <[email protected]>
wrote:
> ## Ron Johnson ([email protected]):
>
> > I need to process table records in a bash script. Currently, I read them
> > using a while loop and redirection. The table isn't that big (30ish
> > thousand rows), and performance is adequate, but am always looking for
> > "better".
>
> Use python, or any other sane language, and don't do bash in python.
> Anything non-trivial is unreasonably hard to get really right when
> using shell.
>
> Take this example (even when allowing some fuzz with the variables):
> > Here's the current code:
> > declare f1 f3 f8
> > while IFS='|' read f1 f3 f8; do
> > something f8 f3 f1
> > done < <(psql -XAt -c "select f1, f3, f8 from some.table_name;")
>
> What happens when f3
> a) is NULL?
> b) contains a '|' character?
> c) contains spaces? (this one depends on how exactly you're handling
> the shell variables).
> This might be fine if your data is only NOT NULL numbers, but that's
> already quite a limitation on your data.
>
Good points. Shouldn't be relevant in my situation, but
defensive programming never hurts.
--
Death to America, and butter sauce.
Iraq lobster!
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