Soft link & hard link

 

[email protected]:/home/shay/Documents/test# cat lnkt2
hello world
[email protected]:/home/shay/Documents/test# ls
lnkt2
[email protected]:/home/shay/Documents/test# ln lnkt2 lnkt1
[email protected]:/home/shay/Documents/test# mkdir testdir1
[email protected]:/home/shay/Documents/test# mv lnk2 ./testdir1/
mv: cannot stat 'lnk2': No such file or directory
[email protected]:/home/shay/Documents/test# mv lnkt2 ./testdir1/
[email protected]:/home/shay/Documents/test# ls
lnkt1  testdir1
[email protected]:/home/shay/Documents/test# tree .
.
├── lnkt1
└── testdir1
    └── lnkt2

1 directory, 2 files
[email protected]:/home/shay/Documents/test# ln testdir1 testdir2
ln: testdir1: hard link not allowed for directory
[email protected]:/home/shay/Documents/test# ln -s testdir1 testdir2
[email protected]:/home/shay/Documents/test# ls
lnkt1  testdir1  testdir2
[email protected]:/home/shay/Documents/test# cd testdir2
[email protected]:/home/shay/Documents/test/testdir2# ls
lnkt2
[email protected]:/home/shay/Documents/test/testdir2# cat lnkt2
hello world
[email protected]:/home/shay/Documents/test/testdir2# cd ..
[email protected]:/home/shay/Documents/test# rm -rf testdir1
[email protected]:/home/shay/Documents/test# ls
lnkt1  testdir2
[email protected]:/home/shay/Documents/test# ll
total 12
drwxr-xr-x  2 root root 4096 Jul  9 02:24 ./
drwxr-xr-x 15 shay shay 4096 Jul  9 02:12 ../
-rw-r--r--  1 root root   12 Jul  9 02:13 lnkt1
lrwxrwxrwx  1 root root    8 Jul  9 02:17 testdir2 -> testdir1

Concept reference ：

Detailed explanation of soft links and hard links | 《Linux It's time to learn 》

INODE Definition and metadata

What is an inode?

Linux must allocate an index node (inode) for every file and directory in the filesystem. Inodes do not store actual data. Instead, they store the metadata where you can find the storage blocks of each file’s data.

Metadata in an inode

The following metadata exists in an inode:

• File type
• Permissions
• Owner ID
• Group ID
• Size of file
• Time last accessed
• Time last modified
• Soft/Hard Links
• Access Control List (ACLs)

Reference resources ：

What are inodes in Linux? -

problem 1：cp -l and ln What's the difference? ？

The result of execution is indistinguishable , Are hard links , The difference lies in cp -l Recursion can be attached .

Reference resources ：hard link - Is there a difference between hardlinking with cp -l or ln? - Unix & Linux Stack Exchange