openssh unix dev - Mar 2021 - "ssh-keygen -R hostname" errors out with non-existent known_hosts

I'm inclined to agree with Damien. It doesn't totally make sense to exit
0. The command hasn't successfully completed in the case in which it
can't find the known_host file.

It may be a success according to your semantics in this instance, but what about
in cases where the known_host file *should* have been found, but wasn't?

On Wed, 24 Mar 2021 02:20:19 +0100 (CET)
Thorsten Glaser <t.glaser at tarent.de> wrote:
> On Wed, 24 Mar 2021, Damien Miller wrote:
> 
> > > Exit 0, please. An absent known_hosts file doesn't contain
the entry
> > > the "ssh-keygen -R hostname" entry is expected to
remove, and the
> > > result should be considered a success for the command.
> 
> Agreed.
> 
> > "grep foo /nonexistent" or "sed -i s/foo/bar
/nonexistent" don't return
> > status 0 either for exactly the same reason.
> 
> This is more of a ,g/entry/d than a /entry/d in ed(1) parlance.
> 
> It?s a convenience command to remove an entry from the list of
> known hosts, whether it exists or not or the file doesn?t even
> exist; it should only fail when the job can?t be done (e.g. the
> file is write-protected).
> 
> Think of it as 'rm -f known_hosts/entry' which won?t fail if
> known_hosts/ doesn?t exist.
> 
> bye,
> //mirabilos
> -- 
> ?MyISAM tables -will- get corrupted eventually. This is a fact of life. ?
> ?mysql is about as much database as ms access? ? ?MSSQL at least descends
> from a database? ?it's a rebranded SyBase? ?MySQL however was born from
a
> flatfile and went downhill from there? ? ?at least jetDB doesn?t claim to
> be a database?	(#nosec)    ??? Please let MySQL and MariaDB finally die!
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-- 
Noah Zalev <noah at zalev.ca>

On Tue, 23 Mar 2021, Noah Zalev wrote:
> It may be a success according to your semantics in this instance, but
> what about in cases where the known_host file *should* have been
> found, but wasn't?
What do you care?

Its job is to ensure the next ssh to that host will not have an old
host key in the way. If there?s no known_hosts file, that?s done.

If you really need to test whether that file exists? test(1) exists.

Don?t complicate things.

bye,
//mirabilos
-- 
?MyISAM tables -will- get corrupted eventually. This is a fact of life. ?
?mysql is about as much database as ms access? ? ?MSSQL at least descends
from a database? ?it's a rebranded SyBase? ?MySQL however was born from a
flatfile and went downhill from there? ? ?at least jetDB doesn?t claim to
be a database?	(#nosec)    ??? Please let MySQL and MariaDB finally die!