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.

INSTALL

sudo apt install libc-bin

sudo apk add musl-utils

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.