Print the inode number in front of every name

Answer

ls -i ls -i a.c b.c ls -id . ls -id ..

`-i` prefixes each listing line with the inode number the directory entry holds. `-id .` is the one to remember: it reports the inode of the *directory you are in* rather than listing its contents, and comparing it with `ls -id ..` shows you two adjacent nodes of the tree.

Sarwar & Koretsky 3e ch4 §4.5.5