Provided by: libnet-ldap-perl_0.5800-1_all 
NAME
Net::LDAP - Lightweight Directory Access Protocol
SYNOPSIS
use Net::LDAP;
$ldap = Net::LDAP->new( 'ldap.bigfoot.com' ) or die "$@";
$mesg = $ldap->bind ; # an anonymous bind
$mesg = $ldap->search( # perform a search
base => "c=US",
filter => "(&(sn=Barr)(o=Texas Instruments))"
);
$mesg->code && die $mesg->error;
foreach $entry ($mesg->entries) { $entry->dump; }
$mesg = $ldap->unbind; # take down session
$ldap = Net::LDAP->new( 'ldap.umich.edu' );
# bind to a directory with dn and password
$mesg = $ldap->bind( 'cn=root, o=University of Michigan, c=us',
password => 'secret'
);
$result = $ldap->add( 'cn=Barbara Jensen, o=University of Michigan, c=US',
attrs => [
'cn' => ['Barbara Jensen', 'Barbs Jensen'],
'sn' => 'Jensen',
'mail' => 'b.jensen@umich.edu',
'objectclass' => ['top', 'person',
'organizationalPerson',
'inetOrgPerson' ],
]
);
$result->code && warn "failed to add entry: ", $result->error ;
$mesg = $ldap->unbind; # take down session
DESCRIPTION
Net::LDAP is a collection of modules that implements a LDAP services API for Perl
programs. The module may be used to search directories or perform maintenance functions
such as adding, deleting or modifying entries.
This document assumes that the reader has some knowledge of the LDAP protocol.
CONSTRUCTOR
new ( HOST, OPTIONS )
Creates a new Net::LDAP object and opens a connection to the named host.
"HOST" may be a host name or an IP address. TCP port may be specified after the host
name followed by a colon (such as localhost:10389). The default TCP port for LDAP is
389.
You can also specify a URI, such as 'ldaps://127.0.0.1:666' or
'ldapi://%2fvar%2flib%2fldap_sock'. Note that '%2f's in the LDAPI socket path will be
translated into '/'. This is to support LDAP query options like base, search etc.
although the query part of the URI will be ignored in this context. If port was not
specified in the URI, the default is either 389 or 636 for 'LDAP' and 'LDAPS' schemes
respectively.
"HOST" may also be a reference to an array of hosts, host-port pairs or URIs to try.
Each will be tried in order until a connection is made. Only when all have failed will
the result of "undef" be returned.
port => N
Port to connect to on the remote server. May be overridden by "HOST".
scheme => 'ldap' | 'ldaps' | 'ldapi'
Connection scheme to use when not using an URI as "HOST". (Default: ldap)
keepalive => 1
If given, set the socket's SO_KEEPALIVE option depending on the Boolean value of
the option. (Default: use system default)
Failures in changing the socket's SO_KEEPALIVE option are ignored.
timeout => N
Timeout passed to IO::Socket when connecting the remote server. (Default: 120)
multihomed => N
Will be passed to IO::Socket as the "MultiHomed" parameter when connecting to the
remote server
localaddr => HOST
Will be passed to IO::Socket as the "LocalAddr" parameter, which sets the client's
IP address (as opposed to the server's IP address.)
debug => N
Set the debug level. See the debug method for details.
async => 1
Perform all operations asynchronously.
onerror => 'die' | 'warn' | undef | sub { ... }
In synchronous mode, change what happens when an error is detected.
'die'
Net::LDAP will croak whenever an error is detected.
'warn'
Net::LDAP will warn whenever an error is detected.
undef
Net::LDAP will warn whenever an error is detected and "-w" is in effect. The
method that was called will return "undef".
sub { ... }
The given sub will be called in a scalar context with a single argument, the
result message. The value returned will be the return value for the method
that was called.
version => N
Set the protocol version being used (default is LDAPv3). This is useful if you
want to talk to an old server and therefore have to use LDAPv2.
raw => REGEX
Use REGEX to denote the names of attributes that are to be considered binary in
search results.
When running on Perl 5.8 and this option is given Net::LDAP converts all values of
attributes not matching this REGEX into Perl UTF-8 strings so that the regular
Perl operators (pattern matching, ...) can operate as one expects even on strings
with international characters.
If this option is not given or the version of Perl Net::LDAP is running on is too
old strings are encoded the same as in earlier versions of perl-ldap.
Example: raw => qr/(?i:^jpegPhoto|;binary)/
inet4 => N
inet6 => N
Try to connect to the server using the specified IP protocol only, i.e. either
IPv4 or IPv6. If the protocol selected is not supported, connecting will fail.
The default is to use any of the two protocols.
Example
$ldap = Net::LDAP->new( 'remote.host', async => 1 );
LDAPS connections have some extra valid options, see the start_tls method for details.
Note the default value for 'sslversion' for LDAPS is 'sslv23', and the default port
for LDAPS is 636.
For LDAPI connections, HOST is actually the location of a UNIX domain socket to
connect to. The default location is '/var/run/ldapi'.
METHODS
Each of the following methods take as arguments some number of fixed parameters followed
by options, these options are passed in a named fashion, for example
$mesg = $ldap->bind( "cn=me,o=example", password => "mypasswd");
The return value from these methods is an object derived from the Net::LDAP::Message
class. The methods of this class allow you to examine the status of the request.
abandon ( ID, OPTIONS )
Abandon a previously issued request. "ID" may be a number or an object which is a sub-
class of Net::LDAP::Message, returned from a previous method call.
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below
callback => CALLBACK
See "CALLBACKS" below
Example
$res = $ldap->search( @search_args );
$mesg = $ldap->abandon( $res ); # This could be written as $res->abandon
add ( DN, OPTIONS )
Add a new entry to the directory. "DN" can be either a Net::LDAP::Entry object or a
string.
attrs => [ ATTR => VALUE, ... ]
"VALUE" should be a string if only a single value is wanted, or a reference to an
array of strings if multiple values are wanted.
This argument is not used if "DN" is a Net::LDAP::Entry object.
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below
callback => CALLBACK
See "CALLBACKS" below
Example
# $entry is an object of class Net::LDAP::Entry
$mesg = $ldap->add( $entry );
$mesg = $ldap->add( $dn,
attrs => [
name => 'Graham Barr',
attr => 'value1',
attr => 'value2',
multi => [qw(value1 value2)]
]
);
bind ( DN, OPTIONS )
Bind (log in) to the server. "DN" is the DN to bind with. An anonymous bind may be
done by calling bind without any arguments.
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below
callback => CALLBACK
See "CALLBACKS" below
noauth | anonymous => 1
Bind without any password. The value passed with this option is ignored.
password => PASSWORD
Bind with the given password.
sasl => SASLOBJ
Bind using a SASL mechanism. The argument given should be a sub-class of
Authen::SASL or an Authen::SASL client connection by calling "client_new" on an
Authen::SASL object.
If passed an Authen::SASL object then "client_new" will be called to create a
client connection object. The hostname passed by "Net::LDAP" to "client_new" can
be set using the "sasl_host" option below. If this is not correct for your
environment, consider calling "client_new" yourself and passing the client
connection object as "SASLOBJ".
sasl_host => SASLHOST
When binding using SASL, allow the hostname used in the SASL communication to
differ from the hostname connected to.
If "SASLHOST" evaluates to TRUE, then it is used as the SASL hostname.
If it evaluates to FALSE, then the value is determined by calling "peerhost" on
the socket. In older versions of Net::LDAP this was the standard behaviour, but
it turned out to cause more trouble than it fixed.
When the option is not given, the SASL host name used defaults to the host name /
IP address taken from the "HOST" parameter when connecting.
Example
$mesg = $ldap->bind; # Anonymous bind
$mesg = $ldap->bind( $dn, password => $password );
# $sasl is an object of class Authen::SASL
$mesg = $ldap->bind( $dn, sasl => $sasl, version => 3 );
compare ( DN, OPTIONS )
Compare values in an attribute in the entry given by "DN" on the server. "DN" may be a
string or a Net::LDAP::Entry object.
attr => ATTR
The name of the attribute to compare.
value => VALUE
The value to compare with.
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below.
callback => CALLBACK
See "CALLBACKS" below.
Example
$mesg = $ldap->compare( $dn,
attr => 'cn',
value => 'Graham Barr'
);
delete ( DN, OPTIONS )
Delete the entry given by "DN" from the server. "DN" may be a string or a
Net::LDAP::Entry object.
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below.
callback => CALLBACK
See "CALLBACKS" below.
Example
$mesg = $ldap->delete( $dn );
moddn ( DN, OPTIONS )
Rename the entry given by "DN" on the server. "DN" may be a string or a
Net::LDAP::Entry object.
newrdn => RDN
This value should be a new RDN to assign to "DN".
deleteoldrdn => 1
This option should be passed if the existing RDN is to be deleted.
newsuperior => NEWDN
If given this value should be the DN of the new superior for "DN".
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below.
callback => CALLBACK
See "CALLBACKS" below.
Example
$mesg = $ldap->moddn( $dn, newrdn => 'cn=Graham Barr' );
modify ( DN, OPTIONS )
Modify the contents of the entry given by "DN" on the server. "DN" may be a string or
a Net::LDAP::Entry object.
add => { ATTR => VALUE, ... }
Add more attributes or values to the entry. "VALUE" should be a string if only a
single value is wanted in the attribute, or a reference to an array of strings if
multiple values are wanted.
$mesg = $ldap->modify( $dn,
add => {
description => 'List of members', # Add description attribute
member => [
'cn=member1,ou=people,dc=example,dc=com', # Add to attribute
'cn=member2,ou=people,dc=example,dc=com',
]
}
);
delete => [ ATTR, ... ]
Delete complete attributes from the entry.
$mesg = $ldap->modify( $dn,
delete => ['member','description'] # Delete attributes
);
delete => { ATTR => VALUE, ... }
Delete individual values from an attribute. "VALUE" should be a string if only a
single value is being deleted from the attribute, or a reference to an array of
strings if multiple values are being deleted.
If "VALUE" is a reference to an empty array or all existing values of the
attribute are being deleted, then the attribute will be deleted from the entry.
$mesg = $ldap->modify( $dn,
delete => {
description => 'List of members',
member => [
'cn=member1,ou=people,dc=example,dc=com', # Remove members
'cn=member2,ou=people,dc=example,dc=com',
],
seeAlso => [], # Remove attribute
}
);
replace => { ATTR => VALUE, ... }
Replace any existing values in each given attribute with "VALUE". "VALUE" should
be a string if only a single value is wanted in the attribute, or a reference to
an array of strings if multiple values are wanted. A reference to an empty array
will remove the entire attribute. If the attribute does not already exist in the
entry, it will be created.
$mesg = $ldap->modify( $dn,
replace => {
description => 'New List of members', # Change the description
member => [ # Replace whole list with these
'cn=member1,ou=people,dc=example,dc=com',
'cn=member2,ou=people,dc=example,dc=com',
],
seeAlso => [], # Remove attribute
}
);
increment => { ATTR => VALUE, ... }
Atomically increment the existing value in each given attribute by the provided
"VALUE". The attributes need to have integer syntax, or be otherwise
"incrementable". Note this will only work if the server advertises support for
LDAP_FEATURE_MODIFY_INCREMENT. Use "supported_feature" in Net::LDAP::RootDSE to
check this.
$mesg = $ldap->modify( $dn,
increment => {
uidNumber => 1 # increment uidNumber by 1
}
);
changes => [ OP => [ ATTR => VALUE ], ... ]
This is an alternative to add, delete, replace and increment where the whole
operation can be given in a single argument. "OP" should be add, delete, replace
or increment. "VALUE" should be either a string or a reference to an array of
strings, as before.
Use this form if you want to control the order in which the operations will be
performed.
$mesg = $ldap->modify( $dn,
changes => [
add => [
description => 'A description',
member => $newMember,
],
delete => [
seeAlso => [],
],
add => [
anotherAttribute => $value,
],
]
);
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below.
callback => CALLBACK
See "CALLBACKS" below.
Example
$mesg = $ldap->modify( $dn, add => { sn => 'Barr' } );
$mesg = $ldap->modify( $dn, delete => [qw(faxNumber)] );
$mesg = $ldap->modify( $dn, delete => { 'telephoneNumber' => '911' } );
$mesg = $ldap->modify( $dn, replace => { 'mail' => 'gbarr@pobox.com' } );
$mesg = $ldap->modify( $dn,
changes => [
# add sn=Barr
add => [ sn => 'Barr' ],
# delete all fax numbers
delete => [ faxNumber => []],
# delete phone number 911
delete => [ telephoneNumber => ['911']],
# change email address
replace => [ mail => 'gbarr@pobox.com']
]
);
search ( OPTIONS )
Search the directory using a given filter. This can be used to read attributes from a
single entry, from entries immediately below a particular entry, or a whole subtree of
entries.
The result is an object of class Net::LDAP::Search.
base => DN
The DN that is the base object entry relative to which the search is to be
performed.
scope => 'base' | 'one' | 'sub' | 'subtree' | 'children'
By default the search is performed on the whole tree below the specified base
object. This maybe changed by specifying a "scope" parameter with one of the
following values:
base
Search only the base object.
one Search the entries immediately below the base object.
sub
subtree
Search the whole tree below (and including) the base object. This is the
default.
children
Search the whole subtree below the base object, excluding the base object
itself.
Note: children scope requires LDAPv3 subordinate feature extension.
deref => 'never' | 'search' | 'find' | 'always'
By default aliases are dereferenced to locate the base object for the search, but
not when searching subordinates of the base object. This may be changed by
specifying a "deref" parameter with one of the following values:
never
Do not dereference aliases in searching or in locating the base object of the
search.
search
Dereference aliases in subordinates of the base object in searching, but not
in locating the base object of the search.
find
Dereference aliases in locating the base object of the search, but not when
searching subordinates of the base object. This is the default.
always
Dereference aliases both in searching and in locating the base object of the
search.
sizelimit => N
A sizelimit that restricts the maximum number of entries to be returned as a
result of the search. A value of 0, and the default, means that no restriction is
requested. Servers may enforce a maximum number of entries to return.
timelimit => N
A timelimit that restricts the maximum time (in seconds) allowed for a search. A
value of 0 (the default), means that no timelimit will be requested.
typesonly => 1
Only attribute types (no values) should be returned. Normally attribute types and
values are returned.
filter => FILTER
A filter that defines the conditions an entry in the directory must meet in order
for it to be returned by the search. This may be a string or a Net::LDAP::Filter
object. Values inside filters may need to be escaped to avoid security problems;
see Net::LDAP::Filter for a definition of the filter format, including the
escaping rules.
attrs => [ ATTR, ... ]
A list of attributes to be returned for each entry that matches the search filter.
If not specified, then the server will return the attributes that are specified as
accessible by default given your bind credentials.
Certain additional attributes such as "createTimestamp" and other operational
attributes may also be available for the asking:
$mesg = $ldap->search( ... ,
attrs => ['createTimestamp']
);
To retrieve the default attributes and additional ones, use '*'.
$mesg = $ldap->search( ... ,
attrs => ['*', 'createTimestamp']
);
To retrieve no attributes (the server only returns the DNs of matching entries),
use '1.1':
$mesg = $ldap->search( ... ,
attrs => ['1.1']
);
control => CONTROL
control => [ CONTROL, ... ]
See "CONTROLS" below.
callback => CALLBACK
See "CALLBACKS" below.
raw => REGEX
Use REGEX to denote the names of attributes that are to be considered binary in
search results.
When running on Perl 5.8 and this option is given Net::LDAP converts all values of
attributes not matching this REGEX into Perl UTF-8 strings so that the regular
Perl operators (pattern matching, ...) can operate as one expects even on strings
with international characters.
If this option is not given or the version of Perl Net::LDAP is running on is too
old strings are encoded the same as in earlier versions of perl-ldap.
The value provided here overwrites the value inherited from the constructor.
Example: raw => qr/(?i:^jpegPhoto|;binary)/
Example
$mesg = $ldap->search(
base => $base_dn,
scope => 'sub',
filter => '(|(objectclass=rfc822mailgroup)(sn=jones))'
);
Net::LDAP::LDIF->new( \*STDOUT,"w" )->write( $mesg->entries );
start_tls ( OPTIONS )
Calling this method will convert the existing connection to using Transport Layer
Security (TLS), which provides an encrypted connection. This is only possible if the
connection uses LDAPv3, and requires that the server advertises support for
LDAP_EXTENSION_START_TLS. Use "supported_extension" in Net::LDAP::RootDSE to check
this.
verify => 'none' | 'optional' | 'require'
How to verify the server's certificate:
none
The server may provide a certificate but it will not be checked - this may
mean you are be connected to the wrong server
optional
Verify only when the server offers a certificate
require
The server must provide a certificate, and it must be valid.
If you set verify to optional or require, you must also set either cafile or
capath. The most secure option is require.
sslversion => 'sslv2' | 'sslv3' | 'sslv23' | 'tlsv1'
This defines the version of the SSL/TLS protocol to use. Defaults to 'tlsv1'.
ciphers => CIPHERS
Specify which subset of cipher suites are permissible for this connection, using
the standard OpenSSL string format. The default value is 'ALL', which permits all
ciphers, even those that don't encrypt.
clientcert => '/path/to/cert.pem'
clientkey => '/path/to/key.pem'
keydecrypt => sub { ... }
If you want to use the client to offer a certificate to the server for SSL
authentication (which is not the same as for the LDAP Bind operation) then set
clientcert to the user's certificate file, and clientkey to the user's private key
file. These files must be in PEM format.
If the private key is encrypted (highly recommended) then keydecrypt should be a
subroutine that returns the decrypting key. For example:
$ldap = Net::LDAP->new( 'myhost.example.com', version => 3 );
$mesg = $ldap->start_tls(
verify => 'require',
clientcert => 'mycert.pem',
clientkey => 'mykey.pem',
keydecrypt => sub { 'secret'; },
capath => '/usr/local/cacerts/'
);
capath => '/path/to/servercerts/'
cafile => '/path/to/servercert.pem'
When verifying the server's certificate, either set capath to the pathname of the
directory containing CA certificates, or set cafile to the filename containing the
certificate of the CA who signed the server's certificate. These certificates must
all be in PEM format.
The directory in 'capath' must contain certificates named using the hash value of
the certificates' subject names. To generate these names, use OpenSSL like this in
Unix:
ln -s cacert.pem `openssl x509 -hash -noout < cacert.pem`.0
(assuming that the certificate of the CA is in cacert.pem.)
checkcrl => 1
If capath has been configured, then it will also be searched for certificate
revocation lists (CRLs) when verifying the server's certificate. The CRLs' names
must follow the form hash.rnum where hash is the hash over the issuer's DN and num
is a number starting with 0.
See "SSL_check_crl" in IO::Socket::SSL for further information.
unbind ( )
The unbind method does not take any parameters and will unbind you from the server.
Some servers may allow you to re-bind or perform other operations after unbinding. If
you wish to switch to another set of credentials while continuing to use the same
connection, re-binding with another DN and password, without unbind-ing, will
generally work.
Example
$mesg = $ldap->unbind;
done ( )
Convenience alias for "unbind()", named after the clean-up method of Net::LDAP::LDIF.
The following methods are for convenience, and do not return "Net::LDAP::Message" objects.
async ( VALUE )
If "VALUE" is given the async mode will be set. The previous value will be returned.
The value is true if LDAP operations are being performed asynchronously.
certificate ( )
Returns an X509_Certificate object containing the server's certificate. See the
IO::Socket::SSL documentation for information about this class.
For example, to get the subject name (in a peculiar OpenSSL-specific format, different
from RFC 1779 and RFC 4514) from the server's certificate, do this:
print "Subject DN: " . $ldaps->certificate->subject_name . "\n";
cipher ( )
Returns the cipher mode being used by the connection, in the string format used by
OpenSSL.
debug ( VALUE )
If "VALUE" is given the debug bit-value will be set. The previous value will be
returned. Debug output will be sent to "STDERR". The bits of this value are:
1 Show outgoing packets (using asn_hexdump).
2 Show incoming packets (using asn_hexdump).
4 Show outgoing packets (using asn_dump).
8 Show incoming packets (using asn_dump).
The default value is 0.
disconnect ( )
Disconnect from the server
root_dse ( OPTIONS )
The root_dse method retrieves cached information from the server's rootDSE.
attrs => [ ATTR, ... ]
A reference to a list of attributes to be returned. If not specified, then the
following attributes will be requested
subschemaSubentry
namingContexts
altServer
supportedExtension
supportedFeatures
supportedControl
supportedSASLMechanisms
supportedLDAPVersion
The result is an object of class Net::LDAP::RootDSE.
Example
my $root = $ldap->root_dse;
# get naming Context
$root->get_value( 'namingContexts', asref => 1 );
# get supported LDAP versions
$root->supported_version;
As the root DSE may change in certain circumstances - for instance when you change the
connection using start_tls - you should always use the root_dse method to return the
most up-to-date copy of the root DSE.
schema ( OPTIONS )
Read schema information from the server.
The result is an object of class Net::LDAP::Schema. Read this documentation for
further information about methods that can be performed with this object.
dn => DN
If a DN is supplied, it will become the base object entry from which the search
for schema information will be conducted. If no DN is supplied the base object
entry will be determined from the rootDSE entry.
Example
my $schema = $ldap->schema;
# get objectClasses
@ocs = $schema->all_objectclasses;
# Get the attributes
@atts = $schema->all_attributes;
socket ( )
Returns the underlying "IO::Socket" object being used.
host ( )
Returns the host to which the connection was established. For LDAPI connections the
socket path is returned.
port ( )
Returns the port connected to or "undef" in case of LDAPI connections.
uri ( )
Returns the URI connected to.
As the value returned is that element of the constructor's HOST argument with which
the connection was established this may or may not be a legal URI.
scheme ( )
Returns the scheme of the connection. One of ldap, ldaps or ldapi.
sync ( MESG )
Wait for a given "MESG" request to be completed by the server. If no "MESG" is given,
then wait for all outstanding requests to be completed.
Returns an error code defined in Net::LDAP::Constant.
process ( MESG )
Process any messages that the server has sent, but do not block. If "MESG" is
specified then return as soon as "MESG" has been processed.
Returns an error code defined in Net::LDAP::Constant.
version ( )
Returns the version of the LDAP protocol that is being used.
CONTROLS
Many of the methods described above accept a control option. This allows the user to pass
controls to the server as described in LDAPv3.
A control is a reference to a HASH and should contain the three elements below. If any of
the controls are blessed then the method "to_asn" will be called which should return a
reference to a HASH containing the three elements described below.
For most purposes Net::LDAP::Control objects are the easiest way to generate controls.
type => OID
This element must be present and is the name of the type of control being requested.
critical => FLAG
critical is optional and should be a Boolean value, if it is not specified then it is
assumed to be false.
value => VALUE
If the control being requested requires a value then this element should hold the
value for the server.
CALLBACKS
Most of the above commands accept a callback option. This option should be a reference to
a subroutine. This subroutine will be called for each packet received from the server as a
response to the request sent.
When the subroutine is called the first argument will be the Net::LDAP::Message object
which was returned from the method.
If the request is a search then multiple packets can be received from the server. Each
entry is received as a separate packet. For each of these the subroutine will be called
with a Net::LDAP::Entry object as the second argument.
During a search the server may also send a list of references. When such a list is
received then the subroutine will be called with a Net::LDAP::Reference object as the
second argument.
LDAP ERROR CODES
Net::LDAP also exports constants for the error codes that can be received from the server,
see Net::LDAP::Constant.
SEE ALSO
Net::LDAP::Constant, Net::LDAP::Control, Net::LDAP::Entry, Net::LDAP::Filter,
Net::LDAP::Message, Net::LDAP::Reference, Net::LDAP::Search, Net::LDAP::RFC
The homepage for the perl-ldap modules can be found at http://ldap.perl.org/.
ACKNOWLEDGEMENTS
This document is based on a document originally written by Russell Fulton
<r.fulton@auckland.ac.nz>.
Chris Ridd <chris.ridd@isode.com> for the many hours spent testing and contribution of the
ldap* command line utilities.
MAILING LIST
A discussion mailing list is hosted by the Perl Foundation at <perl-ldap@perl.org> No
subscription is necessary!
BUGS
We hope you do not find any, but if you do please report them to the mailing list.
If you have a patch, please send it as an attachment to the mailing list.
AUTHOR
Graham Barr <gbarr@pobox.com>
COPYRIGHT
Copyright (c) 1997-2004 Graham Barr. All rights reserved. This program is free software;
you can redistribute it and/or modify it under the same terms as Perl itself.