ldconfig creates the necessary links and cache (for use by the run-time linker, ld.so) to the most recent shared libraries found in the directories specified on the command line, in the file /etc/ld.so.conf, and in the trusted directories (/usr/lib and /lib). ldconfig checks the header and file names of the libraries it encounters when determining which versions should have their links updated. ldconfig ignores symbolic links when scanning for libraries.
Some existing libs do not contain enough information to allow the deduction of their type, therefore the /etc/ld.so.conf file format allows the specification of an expected type. This is only used for those ELF libs which we can not work out. The format is like this not allowed. Also see the -p option.
Directory names containing an = are no longer legal unless they also have an expected type specifier.
Verbose mode. Print current version number, the name of each directory as it is scanned and any links that are created.
Only process directories specified on the command line. Don't process the trusted directories (/usr/lib and /lib) nor those specified in /etc/ld.so.conf. Implies -N.
Don't rebuild the cache. Unless -X is also specified, links are still updated.
Don't update links. Unless -N is also specified, the cache is still rebuilt.
Use conf instead of /etc/ld.so.conf.
Use cache instead of /etc/ld.so.cache.
Change to and use root as the root directory.
Library mode. Manually link individual libraries. Intended for use by experts only.
Print the lists of directories and candidate libraries stored in the current cache.
Use FORMAT for the cache file. Choices are old, new and compat (the default).
-? --help --usage
Print usage information.
In the bootup file /etc/rc having the line
will set up the correct links for the shared binaries and rebuild the cache.
On the command line
execution time linker/loader
File containing a list of colon, space, tab, newline, or comma spearated directories in which to search for libraries.
File containing an ordered list of libraries found in the directories specified in /etc/ld.so.conf. This file is not in human readable format, and is not intended to be edited.
ldconfig's functionality, in conjunction with ld.so, is only available for executables compiled using libc version 4.4.3 or greater.