ldconfig

configures the dynamic linker run-time bindings

TLDR

Update symlinks and rebuild the shared library cache

$ sudo ldconfig

Update symlinks for a specific directory only

$ sudo ldconfig -n [path/to/directory]

Print cached libraries and search for a specific library

$ ldconfig -p | grep [library_name]

Rebuild cache with verbose output

$ sudo ldconfig -v

Use an alternate configuration file

$ sudo ldconfig -f [path/to/ld.so.conf]

SYNOPSIS

ldconfig [options] [directory...]

ldconfig configures the dynamic linker run-time bindings. It creates the necessary symbolic links and cache (stored in /etc/ld.so.cache) to the most recent shared libraries found in directories specified in /etc/ld.so.conf, in trusted directories (/lib and /usr/lib), and those specified on the command line.The cache is used by the run-time linker (ld.so or ld-linux.so) to quickly resolve shared library dependencies without scanning directories at load time. Running ldconfig is typically necessary after installing new shared libraries or modifying /etc/ld.so.conf.

PARAMETERS

-n

Process only specified directories (don't update cache)

-p, --print-cache

Print libraries stored in the cache

-v, --verbose

Verbose mode

-N

Don't rebuild the cache

-X

Don't update symbolic links

-f FILE

Use specified config file instead of /etc/ld.so.conf

-C FILE

Use specified cache file instead of /etc/ld.so.cache.

-r ROOT

Change to and use ROOT as the root directory.

-l

Library mode. Manually link individual libraries.

CAVEATS

Requires root privileges to modify the system cache. Must be run after installing new shared libraries for them to be found by the dynamic linker. Libraries in non-standard paths must be listed in /etc/ld.so.conf or passed on the command line. Package managers typically run ldconfig automatically after installing library packages.

HISTORY

ldconfig is part of the GNU C Library (glibc) and has been essential for dynamic linking on Linux systems since the adoption of shared libraries.