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Editor to share with you what the chattr command in Linux refers to. I hope you will gain a lot after reading this article. Let's discuss it together.

We know that Linux is a multi-user operating system where users can delete files that are of great concern to other users, such as administrators. To avoid this, Linux provides the "chattr" command.

What is the chattr command in Linux?

The chattr command in Linux is a file system command that changes the properties of files in a directory. The main purpose of this command is to make it impossible for users other than superusers to change multiple files.

To put it simply, the 'chattr' command can make files immutable, undeleted, only appended, and so on!

Syntax of chattr

# chattr [operator] [flags] [filename]

At the beginning of the flags string of the chattr command, one of the following operators must appear:

1.'+': adds the selected attribute to the existing attribute of the file.

2.'-': delete the selected attribute.

3.'=': make the selected attribute the only attribute of the file.

The following is a list of common properties and associated flags (flags strings) that can be set or unset using the chattr command:

The A:atime record was not updated.

S: changes are synchronized with updates on disk.

A: the file can only be written if it is opened in append mode.

I: the file cannot be modified (immutable), and the only superuser can unset the property.

J: all file information is updated to the ext3 log before updating to the file itself.

T: tail merging is not allowed.

D: there are no backup candidates when running the dump process.

U: when such a file is deleted, its data is saved so that the user can ask it to cancel the deletion.

However, none of the above commands meet the conditions of the file and can be used on the directory (folder) to protect the directory from deletion or any other similar incident. However, when protecting a directory, it is recommended that you use the flag-R' to recursively protect everything in the specified directory.

Here are the different options for the chattr command:

-R: the list property used to recursively display the directory and its contents.

-V: it displays the version of the program.

-a: lists all the files in the directory, including the name with a period ('.' The directory at the beginning of the

-d: this option lists the directory as a regular file instead of listing its contents.

-v: used to display the version / generation code of the file, etc.

How do I use the Chattr command?

1. Add attributes to the file

Create a new file to test it. For example, a new file, tecadmin.txt, is created using the touch command, and 777 permissions are assigned to the file.

# touch tecadmin.txt# chmod 777 tecadmin.txt# ls-l tecadmin.txt-rwxrwxrwx 1 root root 0 Apr 10 13:10 tecadmin.txt

Now enable the I file attribute

# chattr + I tecadmin.txt

Since we have enabled the I file attribute, let's try to delete this file and we will get the following rm prompt error, even if the file has 777 permissions.

# rm-f tecadmin.txtrm: cannot remove `tecadmin.txt': Operation not permitted

2. Delete the attributes of the file

To clear the attributes of a file, simply use the (-) symbol of the attached attribute. For example, in tecadmin.txt.

# chattr-I tecadmin.txt# lsattr tecadmin.txt- tecadmin.txt

3. Protect the directory

The flag + i' can be used for directories (shown below) to make directories immutable; the flag-Renewal is used to make the call recursive, so that all child files and directories are immutable. This protects the entire directory and its files. Example: folder folder

# chattr-R + I folder/

Delete / delete the folder and its files now, and you will receive the following rm prompt error

# rm-rf folder/ rm: cannot remove 'folder/': Operation not permitted

Use the'- R 'switch, the'-i' flag, and the full path of the folder used to unset permissions again.

# chattr-R-I folder/# rm-rf folder/

This successfully deletes the folder directory.

After reading this article, I believe you have a certain understanding of what the chattr command in Linux refers to. Want to know more about it. Welcome to follow the industry information channel. Thank you for your reading!

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