UNIX Symbolic Links

All files for SFX exist in the global instance. These files are symbolically linked to the local instance, which gives the appearance that they exist there as well.

File Editing

The sfxglb41 instance should remain a clean copy of the SFX installation and files there should not be edited. Instead, perform file localization by editing the files in the local instances, after the symbolic link to the global instance has been broken.

When editing files on an instance other than sfxglb41, bear in mind that most of the files are actually links to files in the sfxglb41 instance. Therefore, it is strongly recommended to use vi as your text editor, since it displays a warning when you are editing a file that is actually a link.

If you want to edit one of the files under the sfxlcl41 instance using vi, you receive a message asking if you want to break the symbolic link. For example, when sfxlcl41 tries to edit the file locater.config_:

vi locater.config_

[break symbolic link 'locater.config_' ?] [y/N]

If you answer Yes, vi creates a copy of the file in the sfxlcl41 instance. If you answer No, vi opens the file residing in the sfxglb41 instance in read-only mode.

It is generally recommended not to make any local changes to any file in the sfxglb41 instance, as these files may be changed without warning during the SFX update.

After editing any mod_perl or configuration file (files that end with .pm or .config), Apache needs to be restarted for that instance so that the changes made to the files can take effect. This can be done either by typing apachectl stop and then apachectl start (with a few seconds interval between the two commands) or via the Server Admin Utility. For more information on using the Server Admin Utility, see Start/Stop Services.

Recreating a Symbolic Link

If you have broken the symbolic link and created a local copy of a file, you can undo your changes and recreate the symbolic link by using the procedure below.

To recreate a broken link:
  1. Log on as the user of the instance in the location that you want to recreate the link.
  2. Delete the local copy of the file. For example, if you want to recreate the link to a target parser for Yahoo under /exlibris/sfx_ver/sfx4_1/sfxlcl41/lib/Parsers/TargetParser/WWW/:

tp

cd WWW

rm Yahoo.pm

  1. Create the symbolic link to the global instance. For the Yahoo example:

(Type the following command on one line.)

ln -s /exlibris/sfx_ver/sfx4_1/sfxglb41/lib/Parsers/TargetParser/WWW/Yahoo.pm