Name
ldconfig - configure dynamic linker run-time bindingsSynopsis
[ -nNvVX ] [ -C\~\ccache ] [ -f\~\c conf ] [ -r\~\c root ] directory \~.\|.\|. -l [ -v ] library \~.\|.\|. -p Description
\%ldconfig creates the necessary links and cache 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, /lib and /usr/lib. On some 64-bit architectures such as x86-64, /lib and /usr/lib are the trusted directories for 32-bit libraries, while /lib64 and /usr/lib64 are used for 64-bit libraries. The cache is used by the run-time linker, ld.so or ld-linux.so. \%ldconfig checks the header and filenames of the libraries it encounters when determining which versions should have their links updated. \%ldconfig should normally be run by the superuser as it may require write permission on some root owned directories and files.
\%ldconfig will look only at files that are named lib*.so* (for regular shared objects) or ld-*.so* (for the dynamic loader itself). Other files will be ignored. Also, \%ldconfig expects a certain pattern to how the symbolic links are set up, like this example, where the middle file ( libfoo.so.1 here) is the SONAME for the library:
libfoo.so -> libfoo.so.1 -> libfoo.so.1.12
Failure to follow this pattern may result in compatibility issues after an upgrade.
Options
(Since glibc 2.2) Use cache format fmt, which is one of old ,new ,or \%compat .Since glibc 2.32, the default is new .Before that, it was \%compat .
Use cache instead of /etc/ld.so.cache.
Use conf instead of /etc/ld.so.conf.
-i --ignore-aux-cache (Since glibc 2.7) Ignore auxiliary cache file.
-l (Since glibc 2.2) Interpret each operand as a library name and configure its links. Intended for use only by experts.
-n Process only the directories specified on the command line; don't process the trusted directories, nor those specified in /etc/ld.so.conf. Implies -N .
-N Don't rebuild the cache. Unless -X is also specified, links are still updated.
-p --print-cache Print the lists of directories and candidate libraries stored in the current cache.
Change to and use root as the root directory.
-v --verbose Verbose mode. Print current version number, the name of each directory as it is scanned, and any links that are created. Overrides quiet mode.
-V --version Print program version.
-X Don't update links. Unless -N is also specified, the cache is still rebuilt.
Files
/lib/ld.so is the run-time linker/loader.
/etc/ld.so.conf contains a list of directories, one per line, in which to search for libraries.
/etc/ld.so.cache contains an ordered list of libraries found in the directories specified in /etc/ld.so.conf, as well as those found in the trusted directories.