Does linux have the in command?

There is an in command in Linux. The in command is used to establish a synchronous link for a certain file in another location. When using the same file, you only need to put the file in a fixed directory and use the in command to connect it in other directories. Syntax is "ln [parameter][source file or directory][destination file or directory]".

#The operating environment of this tutorial: linux7.3 system, Dell G3 computer.

Does Linux have an in command?

ln is another very important command in Linux. Its function is to establish a synchronized link for a certain file in another location. When we need to directory, when using the same file, we don't need to put a file that must be the same in every required directory. We only need to put the file in a fixed directory, and then use ln in other directories. You can just link it with the command without repeatedly occupying disk space.

1. Command format:

 ln [参数][源文件或目录][目标文件或目录]

2. Command function:

In the Linux file system, there is a so-called link, which we can regard as an alias of a file, and links can be divided into two types: hard link Unlike soft links (symbolic links), hard links mean that a file can have multiple names, while soft links generate a special file whose content points to the location of another file. Hard links exist in the same file system, but soft links can span different file systems.

Soft link:

1. Soft link exists in the form of a path. Similar to shortcuts in the Windows operating system

2. Soft links can cross file systems, but hard links cannot

3. Soft links can link to a non-existent file name

4. Soft links can link directories

Hard links:

1. Hard links exist in the form of file copies. But it doesn't take up actual space.

2. It is not allowed to create hard links to directories

3. Hard links can only be created in the same file system

There are two points to note here:

First, the ln command will maintain the synchronization of each linked file, that is to say, no matter where you change, other files will have the same changes;

Second, ln The links are divided into soft links and hard links. The soft link is ln -s source file target file. It will only generate a mirror image of the file at the location you selected and will not occupy disk space. The hard link ln source file Target file, without parameter -s, it will generate a file with the same size as the source file at the location you selected. Whether it is a soft link or a hard link, the file will keep changing synchronously.

The ln command is used to link files or directories. If two or more files or directories are specified at the same time, and the final destination is an existing directory, all previously specified files or directories will be copied to in this directory. If multiple files or directories are specified at the same time, and the final destination is not an existing directory, an error message will appear.

3. Command parameters:

Required parameters:

-b Delete, overwrite previously established links

-d Allow super users to create hard links to directories

-f Forces execution of

-i interactive mode. If the file exists, the user will be prompted whether to overwrite it.

-n Treat symbolic links as general directories.

-s Soft links ( Symbolic link)

-v Display detailed processing

Select parameters:

-S “-S2ecadb8afbdb0af480c1eebe33a8a8bf” or “--suffix =2ecadb8afbdb0af480c1eebe33a8a8bf”

-V “-V23120a9f52b0ed18218697b4763fd39d” or “--version-control=23120a9f52b0ed18218697b4763fd39d”

- -help displays help information

--version displays version information

4． Usage example:

Example 1: Create a soft link to a file

Command:

ln -s log2013.log link2013

Output:

[root@localhost test]# ll
-rw-r--r-- 1 root bin      61 11-13 06:03 log2013.log
[root@localhost test]# ln -s log2013.log link2013
[root@localhost test]# ll
lrwxrwxrwx 1 root root     11 12-07 16:01 link2013 -> log2013.log
-rw-r--r-- 1 root bin      61 11-13 06:03 log2013.log

Instructions:

Create a soft link link2013 for the log2013.log file. If log2013.log is lost, link2013 will be invalid

Example 2: Create a hard link to the file

Command:

ln log2013.log ln2013

Output:

[root@localhost test]# ll
lrwxrwxrwx 1 root root     11 12-07 16:01 link2013 -> log2013.log
-rw-r--r-- 1 root bin      61 11-13 06:03 log2013.log
[root@localhost test]# ln log2013.log ln2013
[root@localhost test]# ll
lrwxrwxrwx 1 root root     11 12-07 16:01 link2013 -> log2013.log
-rw-r--r-- 2 root bin      61 11-13 06:03 ln2013
-rw-r--r-- 2 root bin      61 11-13 06:03 log2013.log

Description:

Create a hard link ln2013 for log2013.log, log2013.log has the same attributes as ln2013

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