Df

Section: User Contributed Perl Documentation (3)
Updated: 2006-06-25
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NAME

Filesys::Df - Perl extension for filesystem disk space information.  

SYNOPSIS

  use Filesys::Df;

  #### Get information by passing a scalar directory/filename value
  my $ref = df("/tmp");  # Default output is 1K blocks
  if(defined($ref)) {
     print "Total 1k blocks: $ref->{blocks}\n";
     print "Total 1k blocks free: $ref->{bfree}\n";
     print "Total 1k blocks avail to me: $ref->{bavail}\n";
     print "Total 1k blocks used: $ref->{used}\n";
     print "Percent full: $ref->{per}\n";

     if(exists($ref->{files})) {
        print "Total inodes: $ref->{files}\n"; 
        print "Total inodes free: $ref->{ffree}\n"; 
        print "Inode percent full: $ref->{fper}\n";
     }
  }

  #### Get information by passing a filehandle
  open(FILE, "some_file");  # Get information for filesystem at "some_file"
  my $ref = df(\*FILE);  
  #### or
  my $ref = df(*FILE);  
  #### or
  my $fhref = \*FILE;
  my $ref = df($fhref);  

  #### Get information in other than 1k blocks
  my $ref = df("/tmp", 8192);  # output is 8K blocks
  my $ref = df("/tmp", 1);     # output is bytes

 

DESCRIPTION

This module provides a way to obtain filesystem disk space information. This is a Unix only distribution. If you want to gather this information for Unix and Windows, use "Filesys::DfPortable". The only major benefit of using "Filesys::Df" over "Filesys::DfPortable", is that "Filesys::Df" supports the use of open filehandles as arguments.

The module should work with all flavors of Unix that implement the "statvfs()" and "fstatvfs()" calls, or the "statfs()" and "fstatfs()" calls. This would include Linux, *BSD, HP-UX, AIX, Solaris, Mac OS X, Irix, Cygwin, etc ...

"df()" requires a argument that represents the filesystem you want to query. The argument can be either a scalar directory/file name or a open filehandle. There is also an optional block size argument so you can tailor the size of the values returned. The default block size is 1024. This will cause the function to return the values in 1k blocks. If you want bytes, set the block size to 1.

"df()" returns a reference to a hash. The keys available in the hash are as follows:

"{blocks}" = Total blocks on the filesystem.

"{bfree}" = Total blocks free on the filesystem.

"{bavail}" = Total blocks available to the user executing the Perl application. This can be different than "{bfree}" if you have per-user quotas on the filesystem, or if the super user has a reserved amount. "{bavail}" can also be a negative value because of this. For instance if there is more space being used then you have available to you.

"{used}" = Total blocks used on the filesystem.

"{per}" = Percent of disk space used. This is based on the disk space available to the user executing the application. In other words, if the filesystem has 10% of its space reserved for the superuser, then the percent used can go up to 110%.

You can obtain inode information through the module as well, but you must call "exists()" on the "{files}" key first, to make sure the information is available. Some filesystems may not return inode information, for example some NFS filesystems.

Here are the available inode keys:

"{files}" = Total inodes on the filesystem.

"{ffree}" = Total inodes free on the filesystem.

"{favail}" = Total inodes available to the user executing the application. See the rules for the "{bavail}" key.

"{fused}" = Total inodes used on the filesystem.

"{fper}" = Percent of inodes used on the filesystem. See rules for the "{per}" key.

There are some undocumented keys that are defined to maintain backwards compatibilty: "{su_blocks}", "{user_blocks}", etc ...

If the "df()" call fails for any reason, it will return undef. This will probably happen if you do anything crazy like try to get information for /proc, or if you pass an invalid filesystem name, or if there is an internal error. "df()" will "croak()" if you pass it a undefined value.

Requirements: Your system must contain "statvfs()" and "fstatvfs()", or "statfs()" and "fstatfs()" You must be running Perl 5.6 or higher.  

AUTHOR

Ian Guthrie IGuthrie@aol.com

Copyright (c) 2006 Ian Guthrie. All rights reserved.
               This program is free software; you can redistribute it and/or
               modify it under the same terms as Perl itself.  

SEE ALSO

statvfs(2), fstatvfs(2), statfs(2), fstatfs(2), df(1), Filesys::DfPortable

perl(1).


 

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