From: Nuby Ruby <nubyruby@...>
Date: 2007-08-29T15:45:10+09:00
Subject: Re: Help parsing simple structured data.

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In my situation it'll always be safe to assume there are no mount points,
but I'll grab your code anyways in case I ever run it on a windows or mac
box.

BTW, here's the code I'm working on, thanks for the tidbit, this little bit
of processing is the bit of code I use most in my daily life, and the
hardest for me to wrap my head around when I play with new langauges.

#!/usr/bin/env ruby

require 'rubygems'
require 'getoptlong'
require 'net/ssh'

opts = GetoptLong.new(
    [ "--host", "-h",   GetoptLong::REQUIRED_ARGUMENT]
  )

hostname = nil
opts.each do |opt, arg|
  case opt
  when '--host'
    hostname = arg
  end
end

if hostname == nil
  puts "Missing --host argument"
  puts "usage: `ssh-test.rb --host hostname"
  exit 0
end


Net::SSH.start( hostname,
                :password=>'somepassword',
                :port=>22,
                :username=>'rubyuser'
                ) do |session|
                  shell = session.shell.open
                  shell.df "-h"
                  sleep 0.5

                  disks = shell.stdout.split("\n")[1..-1] while shell.stdout
?

                  hash = Hash.new {|hash, key| hash[key] = {}}
                  disks.each do |disk|
                    data = disk.split /\s+/
                    device = data[0].sub(%r|^/dev/|, "")
                    %w{size  used  avail  use  mount}.each_with_index do
|field, column|
                      hash[device][field] = data[column+1]
                    end
                  end

                  print hash["md0"]["mount"]
                  puts "\n"
end


On 8/28/07, Dan Zwell <dzwell@gmail.com> wrote:
>
> Nuby Ruby wrote:
> > Dan,
> >
> > That works perfectly, thank you a lot! This type of data I end up
> dealing
> > with day-in and day-out, and this will help a lot.
> >
> > Craig
> >
> > On 8/28/07, Dan Zwell < dzwell@gmail.com> wrote:
> >> Nuby Ruby wrote:
> >>> I'm rather new to Ruby and am trying to figure out how to parse some
> >>> structured data.. This is pretty much the most common problem I run
> into
> >>> and it'd be *really* helpful to see an example to wrap my head around
> >> blocks
> >>> & hashes
> >>>
> >>> The data I'm working with is the output of `df -h` which looks like
> this
> >> :
> >>>
> >>> Filesystem            Size  Used Avail Use% Mounted on
> >>> /dev/md0              9.9G  1.6G  7.8G  17% /
> >>> /dev/md1               60G  154M   57G   1% /data
> >>> /dev/sda1              99M   12M   83M  13% /boot
> >>>
> >>> In the end what I'd like to end up with is to be able to say print
> >>> hash[md0(size)] and have it
> >>> return 9.9G or hash[sda1(Mount)] and have it show the mountpoint of
> >> /boot
> >>> If anyone could help I'd really appreciate it.
> >>>
> >>> Craig
> >>>
> >> Try this:
> >>
> >> rows = `df -h`.split("\n")[1..-1]
> >> hash = Hash.new {|hash, key| hash[key] = {}}
> >> rows.each do |row|
> >>    data = row.split /\s+/
> >>    device = data[0].sub(%r|^/dev/|, "")
> >>    %w{size  used  avail  use  mount}.each_with_index do |field, column|
> >>      hash[device][field] = data[column+1]
> >>    end
> >> end
> >>
> >> After running it, you should be able to find your data in
> >> hash["md0"]["size"] or hash["sda1"]["mount"].
> >>
> >> Does this work for you?
> >>
> >> Dan
> >>
> >>
> >
> Craig,
>
> By the way, I just realized that my script assumes that the mount point
> has no spaces. Nothing horrible will happen if it does, but
> hash[device]["mount"] will only contain the first word, like "/d/My" of
> "/d/My Documents". If you want to fix that, you could replace a few of
> the lines in the above script with these:
>
> >>    %w{size  used  avail  use}.each_with_index do |field, column|
> >>      hash[device][field] = data[column+1]
> >>    end
> >>    hash[device][mount] = data[5..-1].join(" ")
>
> Have fun,
> Dan
>
>

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