What is an inode number?

An inode number is a unique identifier for a file or directory in a filesystem. It contains metadata about the file, such as its size, ownership, permissions, and the location of the data blocks on the disk. Each file is associated with an inode, and the inode number is used by the filesystem to access the file's information. When you create a hard link to a file, both the original file and the hard link share the same inode number, indicating they point to the same data on the disk.