Which of the following commands updates the linker cache of shared libraries?

`mkcache` is not a standard Linux command for managing the shared library linker cache.

`soconfig` is not a standard Linux command and does not exist for this purpose.

`mkldconfig` is not a standard Linux command for updating the linker cache.

`lddconfig` is not a standard Linux command - it is a confusion with `ldd` (which lists shared library dependencies of a binary) and `ldconfig`.

`ldconfig` scans the directories listed in `/etc/ld.so.conf` and standard library paths, then regenerates the shared library cache file `/etc/ld.so.cache`. This cache is read by the dynamic linker (`ld.so`) at runtime to quickly resolve shared library dependencies. It must be run as root after installing new shared libraries to make them available to programs.