#!/usr/local/bin/perl
#
#  This is a unix disk space report generator. It takes df -k's and spits out
#     one report that gives each host's name, the total drive space, total free
#     space available, and the percentage of free space on the system. This is 
#     total space, not separated by drive. Swap space not counted, nor are NFS 
#     mounted file systems. It supports Solaris and Linux, but not AIX. To use 
#     each host must have a separate file named for the host (df -k > HOSTNAME)
#     as that is the way it will be called from the command line. I can login 
#     NIS and just create some of the files. I can log in as root on some 
#     non-NIS machines and use mail (dk -k > HOSTNAME; cat HOSTNAME | mail hck)
#     have several systems that do not have mail access, but I can sftp. I put
#     all the files in one directory and call the script ./disk.pl hosts/*
#     Calling the hosts by name from the command line also allows me to get a
#     report of just one host, or a selection of hosts.
#
#A typical df -k looks like this:
#############################################################
#Filesystem           1k-blocks      Used Available Use% Mounted on
#/dev/dsk/c0t0d0s0      8061757   6306497   1674643  79% /
#/dev/dsk/c0t0d0s1       380815    121164    221570  35% /var
#swap                    534400       216    534184   0% /tmp
#nfs.home.edu:/mounts/pluto4/vol4/u04
#                      43505106  39604270   3465785  92% /u04
#nfs.home.edu:/export/sun4/SunOS5.7/usr/x11
#                      69607865  54714403  14197384  79% /usr/x11
#nfs.home.edu:/export/sun4/SunOS5.7/usr/misc
#                      69607865  54714403  14197384  79% /usr/misc
#nfs.home.edu:/mounts/pluto4/vol4/u04/hck
#                      43505106  39604270   3465785  92% /home/hck
#/vol/dev/dsk/c0t2d0/sol_8_sparc_2
#                        115408    115408         0 100% /cdrom/sol_8_sparc_2
#mail.home.edu:/var/mail
#                      51998176  34547199  16930996  67% /var/mail
#nfs.home.edu:/export/sun4/SunOS5.7/usr/perl-5.6
#                      41562853  38366501   2780724  93% /usr/perl-5.6
#nfs.home.edu:/export/sun4/SunOS5.7/usr/gnu
#                      69607865  54714403  14197384  79% /usr/gnu
#############################################################
#So we know some things about it fast. The only lines of interest are the ones
#  that start with "/" CDROM drives stick out, but could be edited out if
#  needed. NFS drives match the != /\// so they're gone. Headers from mail get
#  wild, but they match != /\// also. Blank lines are the same. The fields we
#  care about are the second and fourth. So we grab them and dump the rest!
#

use strict;
use diagnostics;

my $host;
my $line;

#make a tmp file to read from
open WRITEIT, ">report";

#All relevant hosts have been put on the command line (maybe hosts/*)
#This will generate our data file. I like to see the raw data sometimes.
while($host = pop @ARGV)
{
   chomp $host;
   
   open (READIT, "<$host") || die "\n can\'t open the host file: $!\n";

   print WRITEIT "start of $host\n";
   while($line = <READIT>)
   {
      if($line !~ /^\/.*/){next;}
      if($line =~ /^\/proc.*/){next;}#Proc is not of interest
      $line =~ s/^([^ ]*) *([^ ]*) *[^ ]* *([^ ]*) *[^ ]* (.*)/$2 $3/;
      print WRITEIT "$line";
   }
   print WRITEIT "end of $host\n";
   close READIT;
}
close WRITEIT;

#Now read the data and spit out a report.
open READIT, "<report";
open WRITEIT, ">space";
my @numbers = qw(0 0); #numbers from the data file line
my @space = qw(0 0); #space derived from numbers

while($line = <READIT>)
{
   chomp $line;

   #If this is the beginning of a host report, get the host name 
   #  and make the first entry. Then clear the space variables.
   if($line =~ /^start of.*/)
   {
      $line =~ s/start of (.*)/$1/;
      $host = $line;
      $host =~ s/hosts\/(.*)/$1/;
      print WRITEIT "Space report for $host\n";
      @numbers = qw(0 0);
      @space = qw(0 0);
      next;
   }
   #if this is disk line grab the numbers and add them to the totals
   if($line =~ /^[0-9].*/)
   {
      @numbers = split " ", $line;
      $space[0] = $space[0] + $numbers[0];  
      $space[1] = $space[1] + $numbers[1];  
      next;
   }
   #if this the end of a host report, write the totals with a percentage
   if($line =~ /^end of.*/)
   {
      my $percentage = $space[1] / $space[0];
      #OK so this is a cheap way to format a number, but I didn't want to
      #  change print statements for one line.
      $percentage =~ s/..(..).*/$1%/;
      print WRITEIT "Total space on $host = $space[0]\n";
      print WRITEIT "Total space available $host = $space[1]\n";
      print WRITEIT "Percentage of free space is $percentage\n"; 
      print WRITEIT "\n\n";
   }
}