ldconfig: refresh the shared library cache after installing a .so
Rebuild /etc/ld.so.cache so the dynamic linker finds newly added libraries, and inspect it with ldconfig -p.
Run sudo ldconfig after adding a library (or editing /etc/ld.so.conf.d/), then verify with ldconfig -p | grep libname.
01Command
Command
$ sudo ldconfig && ldconfig -p | grep libtorch02What it does
The dynamic loader does not scan the filesystem at startup — it reads /etc/ld.so.cache, a prebuilt index ldconfig generates from /etc/ld.so.conf.d directories. Drop a .so in /usr/local/lib and the loader still won't find it until you run ldconfig, which is why 'cannot open shared object file' appears even though the file exists. ldconfig -p dumps the whole cached index for verification, and LD_LIBRARY_PATH is the per-user override (used for debugging, not production).
03Risk
!Warning: Don't use LD_LIBRARY_PATH as a permanent fix — it changes library resolution for every process; configure /etc/ld.so.conf.d and run ldconfig instead.
04Undo
✓No undo needed — this command does not change persistent state.
05Sources
- ldconfig(8) — Arch Linux manualEvidence: Documents ldconfig rebuilding /etc/ld.so.cache and the trusted library directories
- ldconfig(8) — Linux manual pageEvidence: ldconfig creates the necessary links and cache to the most recent shared libraries found in the directories specified in /etc/ld.so.conf; -p prints the cache
Last verified: 2026-09-17 · Category: Developer