#! /etc/LOCAL/bin/perl5 -w
# Free, public domain program.

use strict;

# $Source: /local/undoc/RCS/mostspace,v $
# $Id: mostspace,v 1.4 1997/08/16 03:51:21 rdroot Exp $
#
# Given a list of directories, select one which is on a filesystem
# with the most free space.

my $DF = '/local/bin/df';

$::myname = 'mostspace';
$::myname =~ s|.*/||;

$::RCSHEADER = '$Source: /local/undoc/RCS/mostspace,v $' . "\n" .
	'$Id: mostspace,v 1.4 1997/08/16 03:51:21 rdroot Exp $';

$::usage = 
"usage: $::myname [-vtx] [-f list] [ directory ... ] (or -h for help)";

# suppresss perl warnings
$::debug = $::trace = $::verbose = $::opt_h = undef;
$::opt_v = $::opt_t = $::opt_x = undef;

if (@ARGV && $ARGV[0] =~ "^-.+" ) {
   require "getopts.pl";
   &Getopts("vtxhf:");
}

$::debug = $::opt_x;
$::trace = $::opt_t;
$::verbose = $::debug || $::trace || $::opt_v;

if ($::opt_h) {
   &givehelp();
   exit(0);
}

my @dirs;
if ($::opt_f) {
   # read filesystems from list
   open(LIST, $::opt_f) ||
      die "$::myname: error: can't read $::opt_f: $!\n";
   while (<LIST>) {
      chomp;
      /^#/ && next;
      /^\s*$/ && next;
      s/^\s+//;
      s/\s+$//;
      push(@dirs, split(' ', $_));
   }
} else {
   @dirs = @ARGV;
}
   
(@dirs < 1) && die "$::myname: error: no directories\n";

my $space;
my $mostspace = -9999;		# lower than any possible low space value
my $mostdir;
my $dir;
for $dir (@dirs) {
   $space = &df($dir);
   $::debug && print "> $dir has $space M free\n";
   if ($space > $mostspace) {
      $mostspace = $space;
      $mostdir = $dir;
   }
}

print "$mostdir\n";

sub usage_error {
   my($msg) = @_;
   if ($msg) {
      die "$msg\n";
   } else {
      die "$::usage\n";
   }
}

sub givehelp {
   ## require 'local/page.pl';
   ## &page(<<EOF);
   print <<EOF;
$::usage

   -v		Be verbose
   -t		Trace only -- show what would be done but don't do it
   -x		Enable debugging -- for program maintainers

$::RCSHEADER
EOF
}

# Get df output.  This subroutine is system-specific.  Rewrite it to
# suit your system.
#
#	$dir(input):		a directory name on which to do 'df'
#	$DF(global, input):	full pathname of df program
#	function value(output):	megabytes free
#
# $::debug is honored.

sub df {
   my($dir) = @_;
   # get df output for $dir
   open(DF, "$DF $dir|");
   $::debug && print "\n> $DF $dir\n";
   my($device, $kbytes, $used, $avail, $capacity, $mounted);
   while (<DF>) {
      /^Filesystem/ && next;
      ($device, $kbytes, $used, $avail, $capacity, $mounted) = 
							 split(' ', $_);
      $::debug && print ">> $_";
      last;
   }
   defined($avail) || return 0;		# maybe invalid directory
   my $megs = int(($avail / 1024) + 0.5);
   $::debug && print ">> $megs megabytes free\n";
   $megs;
}