# /lib
**/lib** holds the shared libraries required by the binaries in `/bin` and `/sbin`. These are the `.so` files the dynamic linker loads at runtime. The C standard library (`libc.so.6`), the dynamic linker itself (`ld-linux.so.2`), and kernel modules all live here. The constraint is the same as for `/bin`: these libraries must be available before other filesystems are mounted, because `/bin/sh` and the other boot-critical binaries link against them.

```
/lib/x86_64-linux-gnu/libc.so.6     C standard library
/lib/x86_64-linux-gnu/libm.so.6     math library
/lib/x86_64-linux-gnu/libpthread.so.0  POSIX threads
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2  dynamic linker
/lib/modules/6.1.0-28-amd64/        kernel modules for this kernel version
```

`/lib/modules/$(uname -r)/` stores loadable kernel modules — the `.ko` files for device drivers, filesystems, and other kernel extensions that are not compiled in. `modprobe` and `insmod` load them on demand. The `lib32` and `lib64` suffixes (or architecture triplets like `x86_64-linux-gnu`) distinguish libraries for different word sizes on multiarch systems.

On modern distributions using merged `/usr`, `/lib` is a symlink to `/usr/lib`, consolidating all libraries there. The symlink preserves compatibility with paths hardcoded into old binaries and build systems.