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Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands i
From: |
Programmingkid |
Subject: |
Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation |
Date: |
Fri, 17 Aug 2018 15:28:17 -0400 |
> On Aug 17, 2018, at 9:44 AM, Eric Blake <address@hidden> wrote:
>
> On 08/16/2018 08:27 PM, Programmingkid wrote:
>
>> I am by no means an expert at qemu-img. But I did try my best to create what
>> I think should be the new output for qemu-img <command> --help. This is just
>> the text I plan on using in a future patch. It is easier to read right now
>> than it will be in patch form, so please let me know if there are any errors
>> in this documentation. Thank you.
>> <amend>
>
> Just reviewing the first for now, to give you a feel for what to consider.
>
>> usage: qemu-img amend [--object objectdef] [--image-opts] [-p] [-q] [-f fmt]
>> [-t cache] -o options filename
>> Command parameters:
>> -f 'fmt' is the disk image format. It is guessed automatically
>> in most cases.
>
> Bad advice. We WANT users to use -f (if you don't, and the automatic guessing
> sees something that is not raw, but your image SHOULD have been -f raw, then
> you have a security hole: the guest can write anything into a raw image to
> make the host access files it shouldn't based on interpreting the raw file as
> something else). I'd drop the last sentence, and use just the first.
Ok.
>
>> --image-opts Treat filename as a set of image options, instead of a plain
>> filename.
>> -o Used with a comma separated list of format specific options
>> in a
>> name=value format. Use "-o ?" for an overview of the options
>
> Please spell that "-o help", not "-o ?". Otherwise, the user has to quote
> the ? to avoid it globbing into any single-byte file lying around in the
> current directory.
"-o ?" and "-o help" does not appear to work for this command. Maybe it should
be removed.
This is what I tried:
qemu-img amend -o help
qemu-img amend -o ?
This is what I see in both instances: qemu-img: Expecting one image file name
>
>> supported by the used format
>> --object 'objectdef' is a QEMU user creatable object definition. See
>> the
>> qemu(1) manual page for a description of the object
>> properties.
>> The most common object type is a 'secret', which is used to
>> supply passwords and/or encryption keys.
>> -p Display progress bar. If the -p option is not used for a
>> command
>> that supports it, the progress is reported when the process
>> receives a "SIGUSR1" signal.
>> -q Quiet mode - do not print any output (except errors).
>> There's no
>> progress bar in case both -q and -p options are used.
>
> Not your fault, but I don't like it when interfaces take mutually exclusive
> operations but the last one does not win. Either '-p -q' should behave like
> '-q', and '-q -p' behave like '-p' (because we accept the mutual exclusion
> but last one wins), or both forms should error (because they are
> incompatible). But having both forms silently behave like '-q' is evil. So,
> as long as you're willing to patch up interfaces, that's a project to
> consider.
>
>> -t Specifies the cache mode that should be used with the
>> destination file.
>
> And what are those modes? If you're going to be wordy, then give the user
> enough information to be useful. Otherwise, being terse in --help is fine
> (and let the man page be wordy instead).
I don't know what the modes are. Anyone care to fill us in?
>> Example:
>> qemu-img amend -o compat=0.10 -f qcow2 image.qcow2
>
> Where's an example with --image-opts and --object secret?
I prefer examples that I think a user would actually use. The --image-opts and
-object options are not necessary to use this command.
> We're trying to move away from compat=0.10 (also spelled compat=v2), and
> instead start encouraging compat=v3.
So you want this: qemu-img amend -o compat=v3 -f qcow2 image.qcow2
Thank you for reviewing my documentation.
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Max Reitz, 2018/08/13
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Eric Blake, 2018/08/13
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Kevin Wolf, 2018/08/14
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Programmingkid, 2018/08/16
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Eric Blake, 2018/08/17
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation,
Programmingkid <=
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Eric Blake, 2018/08/17
- Re: [Qemu-devel] [PATCH] qemu-img.c: increase spacing between commands in documentation, Programmingkid, 2018/08/18