On Fri, Feb 08, 2019 at 10:47:47AM +0100, Johannes Unglert wrote:
>
> I think I described the error the wrong way.
> In the mkfs manpage there are two -V options:
> One for 'verbose' and one for 'version'.
>
> The two -V options are both written with a capital letter.
> It is ambiguous and I think this should not be intentional.
>
> Please correct me if I'm missing anything here.
I noticed this, and it's weird, but what's there is technically
correct in that it accurately described how mkfs works:
-V, --verbose
Produce verbose output, including all filesystem-specific com‐
mands that are executed. Specifying this option more than once
inhibits execution of any filesystem-specific commands. This is
really only useful for testing.
-V, --version
Display version information and exit. (Option -V will display
version information only when it is the only parameter, other‐
wise it will work as --verbose.)
That is, "mkfs -V" == "mkfs --version".
However "mkfs --verbose -- -Fq -t ext4 /tmp/foo.img 4M" is the same as:
"mkfs -V -- -Fq -t ext4 /tmp/foo.img 4M"
I don't think most people notice this because most people they tend
not to use the mkfs wrapper in this mode. In general, they will use
"mkfs.ext4" instead of "mkfs -t ext4". Which is good because it's
actually a bit buggy:
% mkfs -V -t ext4 -Fq /tmp/foo.img 4M
mkfs from util-linux 2.33.1
mkfs.ext4 ext4 -Fq /tmp/foo.img 4M
mkfs.ext4: invalid blocks '/tmp/foo.img' on device 'ext4'
In general, I generally recommend that people use /sbin/mkfs.ext4 or
/sbin/mke2fs -t ext4, because the mkfs wrapper doesn't add much value,
and it gets confusing which options are parameters are grabbed by
mkfs, and which will get passed to the back-end mkfs program.
Cheers,
- Ted
