[Perl-beginners] File System Sizes....

It's better to know what you got, instead to know what you didn't got.

However, before awk can work, perl substitues $5 with it's value (which
is surely undef).
So you should quote it:
$percent = `df -k | awk '{print \$5}'`;

or use the non-interpolation form
$percent = qx'df -k | awk \'{print $5}\'';

You would have recogniced it when running under use warnings,
as you should always do :-)

Best Wishes,
Andrea

Hi,

I've just about solved the problem for you... I am
obviously a student with too much time on his hands ;-)
However, it is fairly complicated for a beginner example,
but should be quite interesting for the more experienced
"beginner" (like me :)

The line with 'split' is what you are looking for, a simple
variation would be:

my $capacity = (split /\s+/)[4];

I hope you can follow what is happening, at least in a
primative sense. I didn't bother to sort the devices,
since this is a hard thing to do correctly.

If anything, learn that you can create concise and
readable(?) scripts. Take care,

Jonathan Paton

--- PERL SCRIPT STARTS HERE ---
#!/usr/bin/perl -w

use strict;

# Call df function for filesystem information
my %df = %{ df() };

# Check capacity
while (my ($device, $data) = each (%df)) {
my $capacity = $data->{capacity};
do_something($device, $capacity) if (90 < $capacity);
}

# Do something about being full
sub do_something {
my ($device, $capacity) = @_;
print "Warning: Device $device has just $capacity\%
left!\n";
}

# Extract information from df
# and return a hash reference to data
sub df {

# Create hash for all the data retrieved from df
my %df;

# Call and process output of df
foreach( qx(df -k) ) {

# Skip non-data lines
next if /^File/;

# Extract data from this row
my ($device, $blocks, $used, $available, $capacity,
$mountpoint) = split /\s+/;

# Remove newline
chomp($mountpoint);

# Remove percent symbol
$capacity =~ s/\%.*//;

# Stuff an anonymous hash containing row data into %df
$df{$device} = { "blocks" => $blocks,
"used" => $used,
"available" => $available,
"capacity" => $capacity,
"mountpoint" => $mountpoint
};
}
return \%df;
}
--- PERL SCRIPT ENDS HERE ---


__________________________________________________

----- Original Message -----
From: "James Kelty" <jamesk@ashlandagency.com>
To: <beginners@perl.org>
Sent: Monday, November 26, 2001 2:17 PM
Subject: File System Sizes....

[...]

Perhaps this is one of those rare times when a plain
old shell script would better suit your purposes?

df |awk '{print $5}' |tail +2 |tr -d %

.... you get the list from there, and test each partition
in order.

Perhaps there are still certain problems that lend
their solutions to a simple shell script.

Perl appears to be better for the more complex stuff
(which seems to happen every single day here!)

in that case all you need to do is capture the df -k output then regex it.

$percent = `df -k`;
$percent =~/regex_to_capture_number/;

You can try the following

($percent) = `df -k` =~ /(\d+)%/;

Regards
Robert Graham

-----Original Message-----
From: Kipp, James
Sent: 27 November 2001 15:47
To: 'James Kelty'; beginners@perl.org
Subject: RE: File System Sizes....

in that case all you need to do is capture the df -k output then regex it.

$percent = `df -k`;
$percent =~/regex_to_capture_number/;

There you go James !!