It’s a unique number contains the metadata. An inode is a data structure on a filesystem on Linux. All UNIX files have its description stored in a structure called 'inode'. The inode contains info about the file-size, its location, time of last access, time of last modification, permission and so on. Directories are also represented as files and have an associated inode. In addition to descriptions about the file, the inode contains pointers to the data blocks of the file Inode consists of the following fields: • File owner identifier • File type • File access permissions • File access times • Number of links • File size • Location of the file data