From: Mark Hahn <mchahn@...>
Date: 2002-01-01T09:19:51+09:00
Subject: [ruby-talk:29916] Re: How to check free diskspace? (fwd)


No one has answered the main question, which is:

Why is there no support for a platform-independent df in Ruby (or Java for
that matter)?

Any good program that writes to a disk should be able to take preventive
action before a disk fills up.  Waiting for a "disk full" exception is a
recipe for disaster.

-----Original Message-----
From: Mathieu Bouchard [mailto:matju@sympatico.ca]
Sent: Monday, December 31, 2001 4:10 PM
To: ruby-talk ML
Subject: [ruby-talk:29915] Re: How to check free diskspace? (fwd)



On Mon, 31 Dec 2001, Mathieu Bouchard wrote:
> On Tue, 1 Jan 2002, Le Wang wrote:
> > Hi all,
> > I've checked "Programming Ruby", and searched the ML to no avail.  So
> > how do you check free disk space, other than to parse 'df' output?
> Mount = Struct.new(
>   :device,
>   :path,
>   :fs_type,
>   :options,
>   :freq,
>   :passno)
> mounts = File.open("/etc/mtab") {|f|
>   f.map {|x|
>     Mount.new(*x.chomp.split) }}

Er... I forgot to finish the code. This only tells what's mounted and
where.

I realized that, unfortunately, the functionality you really want is
system-dependent. It doesn't seem to be covered by POSIX. GNU's "df"
command (in fileutils package) can use any of several implementations,
including BSD, SysV, AIX, ...

Here's a new version which includes df support.

Mount = Struct.new(
  :device, :path, :fs_type, :options, :freq, :passno,
  :total, :used, :free)

mounts = File.open("/etc/mtab") {|f|
  f.map {|x|
    m = Mount.new(*x.chomp.split)
    m.freq=m.freq.to_i
    m.passno=m.passno.to_i
    m }}

File.popen("sh -c 'LC_ALL=en df -P'") {|f|
  2.times { f.readline }
  f.map{|r|
    dev,*stuff = r.chomp.split /\s+/
    m = mounts.find {|d| d.device == dev }
    m.total,m.used,m.free = stuff[0..2].map{|x| x.to_i }}}

________________________________________________________________
Mathieu Bouchard                   http://hostname.2y.net/~matju