Inodes are associated with precisely one directory entry at a time. However, with hard links it is possible to associate multiple directory entries with a single inode. To create a hard link use ln command as follows:
# ln /root/file1 /root/file2
# ls -l
Above commands create a link to file1. Symbolic links refer to: php
A symbolic path indicating the abstract location of another file. node
Hard links refer to: linux
The specific location of physical data. this
Soft or symbolic links are just like hard links. It allows to associate multiple filenames with a single file. However, symbolic links allows: spa
These links behave differently when the source of the link is moved or removed. unix
You can create symbolic link with ln command:
$ ln -s /path/to/file1.txt /path/to/file2.txt
$ ls -ali
Above command will create a symbolic link to file1.txt. rest
Let us create a directory called foo, enter:
$ mkdir foo
$ cd foo
Copy /etc/resolv.conf file, enter:
$ cp /etc/resolv.conf .
View inode number, enter:
$ ls -ali
Sample output: code
total 152 1048600 drwxr-xr-x 2 vivek vivek 4096 2008-12-09 20:19 . 1015809 drwxrwxrwt 220 root root 143360 2008-12-09 20:19 .. 1048601 -rwxr-xr-x 1 vivek vivek 129 2008-12-09 20:19 resolv.conf
Now create soft link to resolv.conf, enter:
$ ln -s resolv.conf alink.conf
$ ls -ali
Sample output: orm
total 152 1048600 drwxr-xr-x 2 vivek vivek 4096 2008-12-09 20:24 . 1015809 drwxrwxrwt 220 root root 143360 2008-12-09 20:19 .. 1048602 lrwxrwxrwx 1 vivek vivek 11 2008-12-09 20:24 alink.conf -> resolv.conf 1048601 -rwxr-xr-x 1 vivek vivek 129 2008-12-09 20:19 resolv.conf
The reference count of the directory has not changed (total 152). Our symbolic (soft) link is stored in a different inode than the text file (1048602). The information stored in resolv.conf is accessible through the alink.conf file. If we delete the text file resolv.conf, alink.conf becomes a broken link and our data is lost:
$ rm resolv.conf
$ ls -ali
If alink.conf was a hard link, our data would still be accessible through alink.conf. Also, if you delete the soft link itself, the data would still be there. Read man page of ln for more information.
Continue reading rest of the Understanding Linux file system series (this is part VI): blog