bug#7042: df --help does not show `-m' option
On 16/09/10 23:34, Paul Eggert wrote: On 09/16/10 11:21, Eric Blake wrote: document -m, with --block-size=M as the long-option spelling add -g, with --block-size=G as the long-option spelling This doesn't sound like a good idea. Multi-terabyte disks are already here, and df -t is already taken. Also, df -g already means something different in Solaris. Is it really that hard to type df -Bg? Yes I agree the current unit selection options are fine. If we're going to make incompatible changes, I suggest that we solve the problem once and for all, by having df choose the default blocksize dynamically, based on the size of the output line describing the smallest disk. For example, where df currently outputs this: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda111620338002 1437021 11618900981 1% /r/opt /dev/sda2 20971520 1335871 19635650 7% /home/eggert df would notice that the smallest file system is between 1GB and 1TB, so it would default to 1 GB blocks, as follows: Filesystem 1GB-blocks Used Available Use% Mounted on /dev/sda1 11900GB 2GB 11898GB 1% /r/opt /dev/sda2 22GB 2GB 21GB 7% /home/eggert This is much more useful as an output format, because one can visually see which file systems are larger by seeing how many digits are there. Contrast this to the output of df --si: Filesystem Size Used Avail Use% Mounted on /dev/sda1 12T 1.5G12T 1% /r/opt /dev/sda2 22G 1.4G21G 7% /home/eggert which is harder to visually parse that way. That would break lots of scripts I'd say (they should use -P, but many don't). In any case I don't think there is enough benefit in such a format change given the common wide range of device sizes attached to systems. Personally I find the `df -h` format easiest to read. While we're at it, we should fix df so that its columns line up better; that would be another incompatible change, but it'd be worth it on hosts where the file system names are long. We definitely should do this to support languages with side column headings, and `df -B\'1` I've an unfinished local branch to do this with mbsalign() cheers, Pádraig.
bug#7042: df --help does not show `-m' option
Hi, On Fri, Sep 17, 2010 at 09:56:57AM +0100, Pádraig Brady wrote: On 16/09/10 23:34, Paul Eggert wrote: If we're going to make incompatible changes, I suggest that we solve the problem once and for all, by having df choose the default blocksize dynamically, based on the size of the output line describing the smallest disk. For example, where df currently outputs this: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda111620338002 1437021 11618900981 1% /r/opt /dev/sda2 20971520 1335871 19635650 7% /home/eggert df would notice that the smallest file system is between 1GB and 1TB, so it would default to 1 GB blocks, as follows: Filesystem 1GB-blocks Used Available Use% Mounted on /dev/sda1 11900GB 2GB 11898GB 1% /r/opt /dev/sda2 22GB 2GB 21GB 7% /home/eggert This is much more useful as an output format, because one can visually see which file systems are larger by seeing how many digits are there. Contrast this to the output of df --si: Filesystem Size Used Avail Use% Mounted on /dev/sda1 12T 1.5G12T 1% /r/opt /dev/sda2 22G 1.4G21G 7% /home/eggert which is harder to visually parse that way. Yes, especially 1.5G of the 12T disk used looks a lot like 1.5T of 1.5T used. That would break lots of scripts I'd say (they should use -P, but many don't). That's obvious (all three points, sadly). In any case I don't think there is enough benefit in such a format change given the common wide range of device sizes attached to systems. I like Paul's suggestion. Of course there are corner cases (mounting an older USB stick with e.g. 128MB). The base could be selected by the smallest mounted fixed disk. Erik -- [T]he essence of XML is this: the problem it solves is not hard, and it does not solve the problem well. -- The Essence of XML by Jérôme Siméon, Philip Wadler
bug#7042: df --help does not show `-m' option
Pádraig Brady p...@draigbrady.com writes: On 16/09/10 23:34, Paul Eggert wrote: If we're going to make incompatible changes, I suggest that we solve the problem once and for all, by having df choose the default blocksize dynamically, based on the size of the output line describing the smallest disk. For example, where df currently outputs this: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda111620338002 1437021 11618900981 1% /r/opt /dev/sda2 20971520 1335871 19635650 7% /home/eggert df would notice that the smallest file system is between 1GB and 1TB, so it would default to 1 GB blocks, as follows: Filesystem 1GB-blocks Used Available Use% Mounted on /dev/sda1 11900GB 2GB 11898GB 1% /r/opt /dev/sda2 22GB 2GB 21GB 7% /home/eggert That would break lots of scripts I'd say (they should use -P, but many don't). You could use `df -Bauto' for that. Andreas. -- Andreas Schwab, sch...@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 And now for something completely different.
bug#7042: df --help does not show `-m' option
On 09/16/2010 09:20 AM, Pádraig Brady wrote: On 16/09/10 12:59, Petr Pisar wrote: Hello, I found `df' utility from coreutils-8.5 does not describe `-m' option that is mentioned in info page and the program accepts it. -- Petr -m was deprecated in 2001 http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=commit;h=d1772031 It is not mentioned in the info page as far as I can see It's not specified by POSIX It's not used in solaris It _is_ used in FreeBSD Oh - I only tested MirBSD (which is more like OpenBSD). So this is much the same argument as supporting `dd bs=1m` http://lists.gnu.org/archive/html/coreutils/2010-09/msg00028.html Also there was a previous request for `df -g` and `du -g` http://lists.gnu.org/archive/html/bug-coreutils/2009-12/msg0.html Yeah, the 'existing implementation' argument does carry some weight (then again, witness my patch today to nuke 'rm -d' even though that was also based on the 'existing implementation' argument). The only reason one would support these is for compat with FreeBSD, and if we did, we wouldn't want to promote their use through documentation. Or, maybe what we should do is: now: make 'du--megabytes' issue a warning (it is the wrong word for what it does). document -m, with --block-size=M as the long-option spelling add -g, with --block-size=G as the long-option spelling in a few years: remove 'du --megabytes' altogether -- Eric Blake ebl...@redhat.com+1-801-349-2682 Libvirt virtualization library http://libvirt.org
bug#7042: df --help does not show `-m' option
On 09/16/10 11:21, Eric Blake wrote: document -m, with --block-size=M as the long-option spelling add -g, with --block-size=G as the long-option spelling This doesn't sound like a good idea. Multi-terabyte disks are already here, and df -t is already taken. Also, df -g already means something different in Solaris. Is it really that hard to type df -Bg? If we're going to make incompatible changes, I suggest that we solve the problem once and for all, by having df choose the default blocksize dynamically, based on the size of the output line describing the smallest disk. For example, where df currently outputs this: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda111620338002 1437021 11618900981 1% /r/opt /dev/sda2 20971520 1335871 19635650 7% /home/eggert df would notice that the smallest file system is between 1GB and 1TB, so it would default to 1 GB blocks, as follows: Filesystem 1GB-blocks Used Available Use% Mounted on /dev/sda1 11900GB 2GB 11898GB 1% /r/opt /dev/sda2 22GB 2GB 21GB 7% /home/eggert This is much more useful as an output format, because one can visually see which file systems are larger by seeing how many digits are there. Contrast this to the output of df --si: Filesystem Size Used Avail Use% Mounted on /dev/sda1 12T 1.5G12T 1% /r/opt /dev/sda2 22G 1.4G21G 7% /home/eggert which is harder to visually parse that way. While we're at it, we should fix df so that its columns line up better; that would be another incompatible change, but it'd be worth it on hosts where the file system names are long.
