chattr command-change file attributes

The chattr command can change the file attributes of the linux file system. The general format is: +-=[aAcCdDeijsStTu] "aAcCdDeijsStTu" represents the new attributes that can be given to the file. These attributes have the following modes.

1. a: Let the file or directory be for additional purposes only
2. A: When a file with "A" attribute is accessed, its a time record will not be modified
3. c: Save the file or directory after compression
4. d: Exclude files or directories from dumping operations
5. i: Do not change files or directories arbitrarily
6. j: If the file system is installed with the "data=order" or "data=writeback" option, the file with the "j" attribute will write all its data into the ext 3 log before writing to the file itself
7. s: When deleting a file with "s" attribute set, its block will be zeroed and written back to disk
8. S: When modifying a file with the "S" attribute set, the change will be written to the disk synchronously. This is equivalent to the "synchronous" mount option applied to a subset of files
9. u: When deleting a file with the 'u' attribute set, its content will be saved.

Syntax:

chattr [parameter] [file]

Command parameters:

-R	Recursively process all files in the directory
-v	Set file or directory version
-V	Show instruction execution process
+	Open the attribute of the file or directory
-	Turn off the attribute of the file or directory
=	Specifies the attribute of the file or directory

Example

Use the chattr command to prevent a key file in the system from being modified (locked):

[root@linuxstar ~]# chattr +i /etc/resolv.conf

Unlock:

[root@linuxstar ~]# chattr -i /home/omd/h.txt

Let a file only add data to it, but not delete it, applicable to various log files:

[root@linuxstar ~]# chattr +a /var/log/messages