NAME

link  — A dcecp object that manages a soft link in CDS

SYNOPSIS

link create link_name_list  {to target_name | timeout expiration_time extension_time  | attribute attribute_list }

link delete link_name_list

link help  [operation | verbose  ]

link modify link_name_list  [add attribute_list]  [remove attribute_list]  [change attribute_list]

link operations

link show link_name_list  [schema ]

Arguments

link_name_list
A list of one or more names of CDS soft links.

operationThe name of the link  operation for which to display help information. 

Description

The link  object represents a Cell Directory Service (CDS) soft link.  A soft link in CDS contains an attribute that has a name that is the same as the name of the object the soft link points to.  The soft link contains several built-in attributes, but users are free to add their own attributes.  Softlinks can point to objects, directories, and other soft links. 

Attributes

The following CDS-defined attributes may be present in CDS link  objects:

CDS_CTS
Specifies the creation timestamp (CTS) of the soft link. The is a read-only DTS-style time stamp, which is set by the system.

CDS_LinkTarget
Specifies the full name of the directory, object entry, or other soft link to which the soft link points.

CDS_LinkTimeout
Specifies a timeout value after which the soft link is either renewed or deleted.  Its value is a list of two elements enclosed in braces, as follows:

{expiration_time extension_time} 

where:

expiration_time
Is a date and time after which CDS checks for the existence of the soft link’s target and either extends or deletes the soft link.  The value is specified in the format yyyy-mm-dd-hh:mm:ss; portions of it can be defaulted. 

extension_time
Is a period of time by which to extend the soft link’s expiration time (if the server has validated that the target still exists). The value is specified in the format ddd-hh:mm:ss; portions of it can be defaulted. 

CDS_UTS
Specifies the timestamp of the most recent update to an attribute of the soft link.  The value is a read-only DTS-style timestamp, which is set by the system.

See the OSF DCE Administration Guide for more information about link attributes. 

Errors

A representative list of errors that might be returned is not shown here.  Refer to the OSF DCE Problem Determination Guide for complete descriptions of all error messages. 

Operations

link create

Creates a new soft link entry in CDS.  The syntax is as follows:

link create link_name_list {to  target-name[timeout  expiration_time extension_time] |
attribute  attribute_list}

Options

to  target-name
Specifies a single name for the links to point to.  If you do not use this option, you must specify the link target with the attribute  option. 

timeout  expiration_time extension_time
Specifies the expiration time and extension period for all soft links named by the link-name_list argument.  The option syntax is as follows:

{expiration_time extension_time} 

See Attributes for more detailed information about link  timeouts.  If you omit the timeout  option, the link is permanent and must be explicitly deleted. 

attribute  attribute_list
Allows you to specify attributes by using an attribute list. See Attributes for more detailed information about link  attributes. 

The create  operation creates a new soft link entry in CDS.  The required link_name_list argument is a list of one or more full CDS names of the soft links to be created.  This operation returns an empty string on success. 

Privileges Required

You must have i (insert) permission to the directory in which you intend to create the soft link. 

Examples

The following command creates a permanent soft link named /.:/sales/tokyo/price-server that points to an object entry named /.:/sales/east/price-server.  The expiration value indicates that CDS checks that the destination name /.:/sales/east/price-server still exists on June 25,1995, at 12:00 p.m.  If the destination name still exists, the soft link remains in effect another 90 days.  Thereafter, CDS will check that the destination name exists every 90 days. 

dcecp> link create /.:/sales/tokyo/price-server -to \fP
> /.:/sales/east/price-server -timeout {1995-06-25-12:00:0090-00:00:00}
dcecp> 

You can enter the same information as the above example by using the attributes  option, as follows:

dcecp> link create /.:/sales/tokyo/price-server -attribute  
> {{CDS_LinkTarget /.:/sales/east/price-server} {CDS_LinkTimeout  
> {expiration 1995-06-25-12:00:00} {extension 90-00:00:00}} }
dcecp> 

link delete

Removes a link entry from CDS.  The syntax is as follows:

link delete link_name_list  

The delete  operation removes a link entry from CDS.  This task is usually done through a client application.  The required link_name_list argument is a list of one or more full CDS names of the link entry to be removed.  This operation returns an empty string on success. 

Privileges Required

You must have d (delete ) permission to the link entry or A (Admin) permission to the directory that stores the link entry. 

Examples

dcecp> link delete /.:/sales/tokyo/price-server
dcecp>  

link help

Returns help information about the link  object and its operations.  The syntax is as follows:

link help [operation | verbose ]

Options

verboseDisplays information about the link  object. 

Used without an argument or option, the link help  command returns brief information about each link  operation.  The optional operation argument is the name of an operation about which you want detailed information.  Alternatively, you can use the verbose  option for more detailed information about the link  object itself. 

Privileges Required

No special privileges are needed to use the link help command. 

Examples

dcecp> link help
create              Creates the named link.
delete              Deletes the named link.
modify              Adds, removes or changes an attribute in the named link.
show                Returns the attributes of a link.
help                Prints a summary of command-line options.
operations          Returns a list of the valid operations for this command.
dcecp>  

link modify

Changes attributes in the specified soft links.  The syntax is as follows:

link modify link_name_list {[add  attribute_list] [remove  attribute_list]
[change  attribute_list]}

Options

add  attribute_list
Adds one or more new attributes to a soft link or adds values to existing attributes when values are not already present.  Add an attribute type with no value by specifying an attribute type with no value.

remove  attribute_list
Removes an entire attribute or some attribute values from a soft link.  If only the attribute type is specified after the option, the entire attribute is removed.  If an attribute type and value are specified, only that value is removed.  If an attribute or value is not present, an error is returned.

change  attribute_list
Changes one attribute value to another for a soft link. Each attribute in the list has its existing value replaced by the new value given in the attribute list.  For multivalued attributes, all existing values are replaced by all the values listed for the attribute in the attribute list.  If an attribute or value is not present, an error is returned.

The modify operation can be used to change two attributes of a soft link: CDS_LinkTarget and CDS_LinkTimeout.  The argument is a list of names of soft links to be operated on.  The operation takes the add , remove , and change  options to specify an attribute list to describe the changes.  All the changes are performed on each soft link named in the argument.  This operation returns an empty string on success. 

Privileges Required

You must have w (write) permission to the link  object. 

Examples

The following example sets the link expiration time to 1998 and the extension time to 10 days and 0 hours:

dcecp> link modify /.:/depts/emergency -change {
> {CDS_LinkTimeout {expiration 1998-01-20-12:00:00:00} {extension +10-0:0:0}} }
dcecp> 

link operations

Returns a list of the operations supported by the link object.  The syntax is as follows:

link operations

The list of available operations is in alphabetical order except for help  and operations, which are listed last. 

Privileges Required

No special privileges are needed to use the link operations command. 

Examples

dcecp> link operations
create delete modify show help operations
dcecp>  

link show

Returns attribute information associated with specified link entries.  The syntax is as follows:

link show link_name_list [schema ]

Options

schemaThis option returns whether an attribute is single or multivalued.  The type of value is specific to a link, meaning that the same attribute can be single-valued on one link and multivalued on another. 

The show  operation displays attribute information associated with specified link entries.  The required link_name_list argument is a list of one or more full CDS names of the soft links you want to show.  If more than one link is shown, the attributes of all the soft links are concatenated into one list.  The order of the returned attributes is the lexical order of the object identifiers (OIDs) of each attribute for each object. 

Privileges Required

You must have r (read) permission to the link entry. 

Examples

dcecp> link show /.:/depts/emergency
{CDS_CTS 1994-07-11-17:47:59.755+00:00I0.000/00-00-c0-8a-df-56}
{CDS_UTS 1994-07-11-17:52:44.698+00:00I0.000/00-00-c0-8a-df-56}
{CDS_LinkTarget /.../my_cell.acme_health.org/depts/radiology}
{CDS_LinkTimeout
 {expiration 1995-07-11-00:00:00.000}
 {extension +10-10:00:00.000I-----}}
dcecp>
 dcecp> link show /.:/gumby -schema
{CDS-CTS single}
{CDS-UTS single}
{CDS-LinkTarget single}
dcecp>   

Related Information

Commands: dcecp(8dce), clearinghouse(8dce), directory(8dce), object(8dce).