Inode

wikipedia:inode

filename to inode lookup

Inodes store information about files and directories (folders), such as file ownership, access mode (read, write, execute permissions), and file type.

Within a POSIX system, a file has the following attributes[10] which may be retrieved by the stat system call:

• Device ID (this identifies the device containing the file; that is, the scope of uniqueness of the serial number).
• File serial numbers. (Inode)
• The file mode which determines the file type and how the file's owner, its group, and others can access the file.
• A link count telling how many hard links point to the inode.
• The User ID of the file's owner.
• The Group ID of the file.
• The device ID of the file if it is a device file.
• The size of the file in bytes.
• Timestamps telling when the inode itself was last modified (ctime, inode change time), the file content last modified (mtime, modification time), and last accessed (atime, access time).
• The preferred I/O block size.
• The number of blocks allocated to this file.

Related terms

• sar -F
• df -i or df --inodes
• ls -i
• File descriptor
• stat
• inotify
• noatime mount option
• inode_readahead_blks mount option
• Drop caches

See also

• file, File system, directory, touch, mkdir, ls, ln truncate, fallocate, split, stat, inode, File descriptor, superblock, block size (blockdev), fuser, lsof, scrub, chattr, ulimit (nofiles), cp, mv, file (command), mkfifo, chmod