Context-Dependent Path Names - Red Hat ENTERPRISE LINUX 5 - GLOBAL FILE SYSTEM Manual

Chapter 3. Managing GFS
Syncing the device.
Freeing buffers.

3.15. Context-Dependent Path Names

Context-Dependent Path Names (CDPNs) allow symbolic links to be created that point to variable
destination files or directories. The variables are resolved to real files or directories each time an
application follows the link. The resolved value of the link depends on the node or user following the
link.
CDPN variables can be used in any path name, not just with symbolic links. However, the CDPN
variable name cannot be combined with other characters to form an actual directory or file name. The
CDPN variable must be used alone as one segment of a complete path.
Usage
For a Normal Symbolic Link
ln -s Target LinkName
Target
Specifies an existing file or directory on a file system.
LinkName
Specifies a name to represent the real file or directory on the other end of the link.
For a Variable Symbolic Link
ln -s Variable LinkName
Variable
Specifies a special reserved name from a list of values (refer to
Values") to represent one of multiple existing files or directories. This string is not the name of an
actual file or directory itself. (The real files or directories must be created in a separate step using
names that correlate with the type of variable used.)
LinkName
Specifies a name that will be seen and used by applications and will be followed to get to one of
the multiple real files or directories. When LinkName is followed, the destination depends on the
type of variable and the node or user doing the following.
Variable
@hostname
@mach
40
Description
This variable resolves to a real file or directory named with the
hostname string produced by the output of the following command:
echo `uname -n`
This variable resolves to a real file or directory name with the machine-
type string produced by the output of the following command: echo
`uname -m`
Table 3.5, "CDPN Variable