Re: df: --inodes versus --portability mode

[Pádraig Brady]

On 09/18/2012 10:47 AM, Bernhard Voelker wrote:
> According to the info pages, the -P mode is like the default mode:
>
> `-P'
> `--portability'
>       Use the POSIX output format.  This is like the default format
>       except for the following:
>
>         1. The information about each file system is always printed on
>            exactly one line; a mount device is never put on a line by
>            itself.  This means that if the mount device name is more
>            than 20 characters long (e.g., for some network mounts), the
>            columns are misaligned.

That should be updated. We no longer split to multiple lines
(though you could leave that assertion).
We should remove the mention about misaligned cols which is no longer the case

>         2. The labels in the header output line are changed to conform
>            to POSIX.
>
>         3. The default block size and output format are unaffected by the
>            `DF_BLOCK_SIZE', `BLOCK_SIZE' and `BLOCKSIZE' environment
>            variables.  However, the default block size is still affected
>            by `POSIXLY_CORRECT': it is 512 if `POSIXLY_CORRECT' is set,
>            1024 otherwise.  *Note Block size::.
>
> BTW: I don't see in the code why df would split an entry on several lines.

Yep I removed that.

> To my question:
> Reading the above, I would assume that -P would override a previous
> -i (or be mutually exclusive to that), but it doesn't:
>
>    $ df -iP | head -n 2
>    Filesystem       Inodes   IUsed    IFree IUse% Mounted on
>    rootfs           768544  237523   531021   31% /
>
> For the implementation of the new --output option, and the cleanup
> necessarily coming with it, I'd like to fix that so that a -P will
> override a previous -i and vice versa:
>
>    $ src/df -iP | head -n 2
>    src/df: warning: option '-P' is overriding the previous mode
>    Filesystem     1024-blocks      Used Available Capacity Mounted on
>    rootfs            12095032   7515424   3965208      66% /
>
>    $ src/df -Pi | head -n 2
>    src/df: warning: option '-i' is overriding the previous mode
>    Filesystem       Inodes   IUsed    IFree IUse% Mounted on
>    rootfs           768544  237523   531021   31% /
>
> WDYT?

I don't like order being significant.
du -i is an extension to POSIX, so I think it's fine for -i to override.
-P essentially meant don't wrap but that's moot now,
but I'd keep it as is for backwards compat.

thanks,
Pádraig.