Section: Linux Programmer's Manual (8)
ldconfig - configure dynamic linker run-time bindings
] [-f conf
] [-C cache
] [-r root
creates the necessary links and cache to the most recent shared
libraries found in the directories specified on the command line,
in the file
and in the trusted directories,
(on some 64-bit architectures such as x86-64,
are the trusted directories for 32-bit libraries, while
are used for 64-bit libraries).
The cache is used by the run-time linker,
checks the header and filenames of the libraries it encounters when
determining which versions should have their links updated.
will attempt to deduce the type of ELF libraries (i.e., libc5 or libc6/glibc)
based on what C libraries, if any, the library was linked against.
Some existing libraries do not contain enough information
to allow the deduction of their type.
file format allows the specification of an expected type.
This is used
for those ELF libraries which we can not work out.
is "dirname=TYPE", where TYPE can be libc4, libc5, or libc6.
(This syntax also works on the command line.)
Also see the
should normally be run by the superuser as it may require write
permission on some root owned directories and files.
will only look at files that are named
(for regular shared objects) or
(for the dynamic loader itself).
Other files will be ignored.
expects a certain pattern to how the symlinks are set up, like this
example, where the middle file
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.
- -c fmt, --format=fmt
(Since glibc 2.2)
Cache format to use:
Since glibc 2.32, the default is
Before that, it was
- -C cache
- -f conf
- -i, --ignore-aux-cache
(Since glibc 2.7)
Ignore auxiliary cache file.
(Since glibc 2.2)
Manually link individual libraries.
Intended for use by experts only.
Process only the directories specified on the command line.
Don't process the trusted directories,
nor those specified in
Don't rebuild the cache.
is also specified, links are still updated.
- -p, --print-cache
Print the lists of directories and candidate libraries stored in
the current cache.
- -r root
Change to and use
as the root directory.
- -v, --verbose
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.
Don't update links.
is also specified, the cache is still rebuilt.
File containing a list of directories, one per line,
in which to search for libraries.
File containing an ordered list of libraries found in the directories
as well as those found in the trusted directories.
This page is part of release 5.10 of the Linux
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at