Article 5272 of comp.lang.perl:

Article 5272 of comp.lang.perl:
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From: [email protected] (Aaron Sherman)
Subject: Re: determining available disk space
In-Reply-To: [email protected]'s message of Fri, 20 Aug 1993 11:29:43 GMT
Message-ID: <[email protected]>
Sender: [email protected]
Organization: I-Kinetics, 19 Bishop-Allen Dr., Cambridge, MA
References: <[email protected]>
Date: Tue, 24 Aug 1993 19:30:15 GMT
Lines: 157

>>>>> [email protected] (Jeff Moskow) said:

jeff> Is there any machine independent way of determining the about of
jeff> available disk space on a particular partition? Basically, I
jeff> want to know if I have enough space to complete an operation
jeff> before I begin. I can certainly execute a df and parse the
jeff> results, but this requires additional code for each new system
jeff> that the script will support. Am I missing something?

Well, I can offer the following.

This is a script which parses df output on Suns, and if we get enough
people to get it to work on their systems, then we will have a
general-purpose program.

I call this dfscan, and it works in a similar fashion to printf, et
al. To use it, you just need to execute dfscan with a format string,
and any arguments that you want passed on to df. So, to find out how
much space is used on /usr, just type "dfscan %c /usr".

-AJS

#!/usr/local/bin/perl
#
# Scan output of df and provide it via command-line options
# By Aaron Sherman (I-Kinetics, Inc.), 1993
#
# $Id$

$0 =~ s/^.*\///;
$usage = "Usage: $0 [-f <file>] [-h <hostname>] [--]
<format> [<df options>]\n";
$file = undef;
$format = undef;
%mapping= ( # Mapping of format letter to field number
'f',0, # Filesystem
't',1, # Total space
'u',2, # Space used
'a',3, # Space available
'c',4, # Capacity
'p',4, # Percent (same as c)
'm',5, # Mount-point
'h',6, # Host
's',6 # Server (same as h)
);
$host = `hostname`;
chop($host);

while(defined($arg = shift))
{
if ($arg =~ s/^-//)
{
if ($arg eq 'f') # File to read for df output
{
die $usage unless(defined($file = shift));
}
elsif ($arg eq 'h') # Host name
{
die $usage unless(defined($host = shift));
}
elsif ($arg eq '-') # End argument processing
{
die $usage unless(defined($format = shift));
last;
}
else
{
die $usage;
}
}
else
{
$format = $arg;
last;
}
}

die $usage unless(defined($format));

@options = @ARGV;

if (defined($file))
{
open(IN,"<$file") || die("$0: Cannot open \"$file\": $!\n");
}
else
{
$cmd = 'df '.join(' ',@options);
open(IN,"$cmd |") || die("$0: Cannot fork: $!\n");
}

while(<IN>)
{
chop;

next if (/^File/); # Header

if ($cont ne '') # Continued lines
{
substr($_,0,0) = $cont;
$cont = '';
}
else
{
if (/^\S+\s*$/)
{
$cont = $_;
next;
}
}

die "$0: Unexpected df output on line $.\n"
unless((@fields = split(/\s+/,$_)) == 6);
if ($fields[0] =~ /^(\S+):/)
{
push(@fields,$1);
}
else
{
push(@fields,$host);
}
$fields[4] =~ s/\%$//;

&out($format,@fields);
}

exit 0;

sub out
{
local($output,@f) = @_;
local($i,$m);

$output =~ s/\%(.)/($1 eq "%")?"%":&form($1,@f)/eg;
print $@ if $@;
print $output, "\n";
}

sub form
{
local($c,@f) = @_;

unless (defined($mapping{$c}))
{
die "$0: No mapping for \"\%$c\".\n";
}
$f[$mapping{$c}];
}
__END__
--
Aaron Sherman I-Kinetics, Inc.
Systems Engineer "Open Systems Stepstones"
Voice: (617)661-8181 19 Bishop Allen Dr.
Fax: (617)661-8625 Cambridge, MA 02139
Pager: (508)545-0584 [email protected]