In Linux, an inode (index node) is a data structure that describes a file system object such as a file or a directory. Each inode stores the attributes and disk block locations of the file system object it describes. Inodes store metadata such as file type, file size, owner ID, group ID, read, write and execute permissions, last access time, last change time, and last modification time. Inodes are used to keep track of all the files and directories within a Linux or UNIX-based file system. They are important for the proper functioning of the operating system and help the system organize data. Inodes do not store actual data, but instead, they store the metadata where you can find the storage blocks of each files data. Every file and directory in a file system is allocated an inode, which is identified by an integer known as the inode number. The inode number indexes a table of inodes on the file system, and from the inode number, the kernels file system driver can access the inode contents, including the location of the file, thereby allowing access to the file. The ls -i command can be used to find a files inode number.