checkzone from stdin?
Grant Taylor
gtaylor at tnetconsulting.net
Wed Apr 8 20:22:56 UTC 2020
On 4/8/20 1:55 PM, Anand Buddhdev wrote:
> named-checkzone wants a file, so give it a "file":
>
> named-checkzone ripe.net. /dev/stdin < ripe.net.zone
You might also consider <(...) files.
named-checkzone example.com <(cat example.com.db)
> Note that it would work with "cat file | ..." but I absolutely hate
> the cat-pipe combination. I've been known to mark down interviewees
> who offer a solution that involves cats and pipes :)
Is cat superfulous, probably. But I'm quite willing to overlook the
useless use of cat if it's a junior admin who's still learning about
stringing commands together.
I'll give a nod of approval if someone says something to the effect of:
Yes, I can remove cat and redirect in from the file, but that
changes the command, slightly, from what would be used elsewhere.
Seeing how cat tempfile is a stand in for a larger more resource
intensive purpose....
I digress.
> If you want to feed a compressed zone file, then of course a
> gzcat-pipe combination will work, eg:
>
> gzcat ripe.net.zone.gz | named-checkzone ripe.net. /dev/stdin
named-checkzone ripe.net. <(gzcat ripe.net.zone.gz)
> Finally, if you're running your scripts under bash, then bash offers
> a very neat feature:
More than just Bash supports it.
I've been using it in Zsh for years. And bash for years before switching.
> named-checkzone ripe.net. <(gzcat ripe.net.zone.gz)
>
> The "<(...)" construct in bash runs the command inside the parantheses,
> and sends its output to an ephemeral file of the form /dev/fd/42. So the
> above command becomes:
>
> named-checkzone ripe.net. /dev/fd/42
>
> and named-checkzone reads the "file" /dev/fd/42, getting the
> decompressed data.
Thank you for the detailed explanation.
--
Grant. . . .
unix || die
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