The chattr command is used to change the attributes of a file or directory. The following table describes some of the options of the chattr command.
| Option | Description |
|---|---|
| -R | Recursively change the attributes of directories and their contents. |
| -v {version} | Set the version number of a file. |
| +i | Mark the file as read-only, or immutable. Requires superuser privileges. |
| -i | Remove the read-only, or immutable, attribute of the file. Requires superuser privileges. |
The syntax of the chattr command is:
# chattr [-R] [-v {version}] [+-{attributes}] {file/directory names} If you encounter the below error while running the chattr command:
chattr: command not found
you may install below package as per your choice of distribution:
| Distribution | Command |
|---|---|
| OS X | brew install e2fsprogs |
| Debian | apt-get install e2fsprogs |
| Ubuntu | apt-get install e2fsprogs |
| Alpine | apk add e2fsprogs |
| Arch Linux | pacman -S e2fsprogs |
| Kali Linux | apt-get install e2fsprogs |
| CentOS | yum install e2fsprogs |
| Fedora | dnf install e2fsprogs |
| Raspbian | apt-get install e2fsprogs |
Removing the -i (immutable) attribute from the files
To Remove “i” attribute use below command.
# chattr -i geek.txt # Unset "i" attribute
After removing the attribute you will see the permission section will become blank.
# lsattr geek.txt --------------- geek.txt
Making a directory immutable using chattr
Now let’s try to Secure a directory by changing it’s attribute recursively using chattr command. Here I have a directory named data and everyone have full access to that directory recursively. Refer the sample output below.
# mkdir data # chmod -R 777 data/ # ls -l total 4 drwxrwxrwx. 2 root root 4096 Apr 24 04:25 data
Now set attribute to that directory.
# chattr +i data/ # lsattr ----i--------e- ./data
You can also set attribute Recursively using -R option with chattr.
# chattr -R +i data/
After setting the attribute to the directory now try to delete, move or create a file, I am sure you will not allowed to do any one of that. Refer the sample output below.
# rmdir data/ # Deleting the Directory rmdir: failed to remove `data/': Operation not permitted
# rm -rf data/ # Deletiing the Directory Forcefully rm: cannot remove `data': Operation not permitted
# mv data/ mydata # Moving the Directory mv: cannot move `data/' to `mydata': Operation not permitted
# cd data/ # cat > test.txt # Creating a File in the directory bash: test.txt: Permission denied