ldconfig(8)                                                                                                                        ldconfig(8)


       ldconfig - configure dynamic linker run-time bindings


       ldconfig [OPTION...]


       ldconfig  creates, updates, and removes 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.

       ldconfig will attempt to deduce the type of ELF libs (ie. libc 5.x or libc 6.x (glibc)) based on what C libraries if  any  the  library
       was linked against, therefore when making dynamic libraries, it is wise to explicitly link against libc (use -lc).  ldconfig is capable
       of storing multiple ABI types of libraries into a single cache on architectures which allow  native  running  of  multiple  ABIs,  like
       ia32/ia64/x86_64 or sparc32/sparc64.

       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
       "dirname=TYPE",  where  type can be libc4, libc5 or libc6.  (This syntax also works on the command line).  Spaces are not allowed. Also
       see the -p option.

       Directory names containing an = are no longer legal unless they also have an expected type specifier.

       ldconfig should normally be run by the super-user as it may require write permission on some root owned directories and files.  If  you
       use  -r  option  to  change  the  root  directory,  you don't have to be super-user though as long as you have sufficient right to that
       directory tree.


       -v --verbose
              Verbose mode.  Print current version number, the name of each directory as it is scanned and any links that are created.

       -n     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.

       -N     Don't rebuild the cache.  Unless -X is also specified, links are still updated.

       -X     Don't update links.  Unless -N is also specified, the cache is still rebuilt.

       -f conf
              Use conf instead of /etc/ld.so.conf.

       -C cache
              Use cache instead of /etc/ld.so.cache.

       -r root
              Change to and use root as the root directory.

       -l     Library mode.  Manually link individual libraries.  Intended for use by experts only.

       -p --print-cache
              Print the lists of directories and candidate libraries stored in the current cache.

       -c --format=FORMAT
              Use FORMAT for the cache file. Choices are old, new and compat (the default).

       -i --ignore-aux-cache
              Ignore auxiliary cache file.

       -? --help --usage
              Print usage information.

       -V --version
              Print version and exit.


              # /sbin/ldconfig -v
       will set up the correct links for the shared binaries and rebuild the cache.
              # /sbin/ldconfig -n /lib
       as root after the installation of a new shared library will properly update the shared library symbolic links in /lib.


       /lib/ld-linux.so.*  execution time linker/loader
       /etc/ld.so.conf     File  containing  a  list  of  colon,  space,  tab,  newline, or comma separated directories in which to search for
       /etc/ld.so.cache    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.
       lib*.so.version     shared libraries


       ldd(1), ld.so(8).


       ldconfig, being a user process, must be run manually and has no means of dynamically determining and relinking shared libraries for use
       by ld.so when a new shared library is installed.


       Andreas Jaeger.  Manual page written by David Engel and Mitch D'Souza.

                                                               25 February 2008                                                    ldconfig(8)

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