Re: [libvirt] [PATCH 1/3] virt-xml-validate: add --help/--version option
On 08/19/2013 07:51 PM, Guan Nan Ren wrote:
> This treats '-' as an unrecognized option (which is a bit
misleading,
> since in POSIX terminology a lone - is NOT an option but an argument).
> It also raises the question - should we allow for an XMLFILE of '-' to
> mean reading from stdin, the way POSIX recommends? That is, should we
> support:
>
> virsh dumpxml $dom | virt-xml-validate -
grep use "grep -f -" to donate the standard input. As written in its manpage
-f is specified by POSIX. If we use -f, the single hyphen can be used
as a filename. But as you said in the follow, user can prefix the filename
with a path - ./-, or /home/Tim/-, so it is still fine in this case.
Actually, 'grep -f - file' and 'grep pattern -' are two quite different
uses of '-' meaning stdin (one treats stdin as the file containing the
pattern, the other treats stdin as the file to search). But yes, the
point is that since POSIX requires '-' to mean stdin when possible,
people are used to that idiom, and used to using ./- when wanting to
refer to a file literally named -.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
Attachments:
- signature.asc (application/pgp-signature — 621 bytes)