Show how 
  ar t 
lists objects in a static library file and
E.g.:

  ar t /usr/lib/gcc/x86_64-linux-gnu/7/libc.a
  ar t /usr/lib/gcc/x86_64-linux-gnu/7/libgcc.a

 nm -D /usr/lib/x86_64-linux-gnu/libgc.so.1
 
lists objects in a dynamically linked shared object file.

 
  
Show how
  ldd <executable>
lists the shared libraries that must be linked into the executable
  ldd /bin/bash

Mention the size command and add it to slides