Explain What Is Ldconfig

NAME
       /sbin/ldconfig - configure dynamic linker run time bindings

SYNOPSIS
       /sbin/ldconfig  [  -nNvXV ] [ -f conf ] [ -C cache ] [ -r root ] direc-
       tory ...
       /sbin/ldconfig -l [ -v ] library ...
       /sbin/ldconfig -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).  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 will attempt to deduce the type of  ELF  libs  (ie.  libc5  or
       libc6/glibc)  based  on  what  C  libs,  if any, the library was linked
       against.  Therefore, when making  dynamic  libraries,  it  is  wise  to
       explicitly link against libc (use -lc).

       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 "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.
       ldconfig  should  normally  be  run  by the superuser as it may require
       write permission on some root owned directories and files.

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

       -n     Only process directories specified on the command  line.   Donât
              process  the  trusted  directories (/lib and /usr/lib) nor those
              specified in /etc/ld.so.conf.  Implies -N.

       -N     Donât rebuild the cache.  Unless -X is also specified, links are
              still updated.

       -X     Donât  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.