LINUX
COMMANDS
Contents | Previous
| Next
Inodes and hard links
Representing a file with a filename, helps users better
relate to it. A file though, is really indicated by an inode
number. The same goes for each directory, which is just
a special file storing the inode numbers to itself (.),
its parent (..), the files it contains, and its
subdirectories.
To view the inode numbers of a directory, enter:
ls -i (or ls -ai to include hidden
files)
To better understand inodes, enter the following two commands:
$ ls -id /usr
293761 /usr
$ ls -id /usr/bin/..
293761 /usr/bin/..
Notice how the .. directory and the usr
directory share the same inode.
When you enter ls -l the second column displays
the number of hard links. This being the number of files
that point to the same inode.
A file will usually have just one hard link, whilst a directory
has at least two (e.g. /bin and /bin/.).
A directory with four hard links indicates it has two subdirectories,
for example:
$ ls -ld /boot
drwxr-xr-x 4 root root 1024 Feb 4 14:48 /boot
4 is displayed because the following directories all point
to the same inode:
/boot
/boot/.
/boot/grub/..
/boot/lost+found/..
Renaming a file or directory doesn't change its inode,
and neither does moving it, so long as the file or directory
is being moved to the same partition. Copying a file though
would give the new file a new inode. (The same going for
a directory and its content.)
None of this section you need to know at beginner level,
but it does help better understand how things work.
Contents | Previous
| Next
