To make our files more secure, Linux provides a feature called file attribute. By configuring the attributes of the file, we can specify whether it is read-only or undeleted, or in other statuses.

List File Attributes

Here are some options for lsattr command:

Let’s first prepare some files and directories:

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mkdir -p attr_dir/attr_dir_child
touch attr_dir/{file{1,2},attr_dir_child/file_child{1,2}}
tree attr_dir

The lsattr command iterates all files and directories contained in the specified directory by default but does not iterate through the files or directories under its subdirectories:

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lsattr attr_dir

Iterate Recursively

With the -R option, we can iterate all the contents of the directory and everything under its subdirectories:

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lsattr -R attr_dir

Include Directory Itself and Parent Directory

With the -a option, we can iterate all of the contents under the specified directory, including itself and its parent directory:

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lsattr -a attr_dir

Directory Itself Only

With the -d option, we can display only the directory itself, not everything under it:

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lsattr -d attr_dir

Long Name Instead of Char Abbreviation

With the -l option, we can display the long name of the option rather than the acronyms:

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lsattr -l attr_dir

Version or Generation Number

With the -v option, we can list version or general numbers of files and directories.

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lsattr -v attr_dir

Change File Attributes

Here are some options for chattr command:

Here are all the mode options for chattr command: (Most options work only on older file system types.)

Mode options supported with xfs type file systems:

Mode options supported with ext4 type file systems:

Mode operations:

We can use the df command followed by the -T option to view the file system type of the partition in which the root path resides:

Assign Attributes

With the equal sign(=), we can assign attributes to files or directories:

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lsattr attr_dir
chattr =i attr_dir/file1    # Assign immutable attribute to file1 under the directory
lsattr attr_dir

Or we can set the attribute verbosely:

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chattr -i attr_dir/file1    # This removes the immutable attribute
lsattr attr_dir
chattr -V =i attr_dir/file1
lsattr attr_dir

When we try to open and save the file, vi prompts that it is a read-only file and can not save the changes:

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vim attr_dir/file1

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:wq

Even if the save command is followed by an exclamation point, it is also impossible to save the file:

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:wq!

Append Attributes

With the plus sign(+), we can append attributes to files or directories:

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lsattr -R attr_dir
chattr -R +aAdS attr_dir/*    # This appends aAdS attributes to all the files and directories under the attr_dir directory
lsattr -R attr_dir

Remove Attributes

With the minus sign(-), we can remove attributes from files or directories:

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lsattr -R attr_dir
chattr -R -aAdiS attr_dir/*    # This removes aAdiS attributes from all the files and directories under the attr_dir directory
lsattr -R attr_dir

References LSATTR(1), CHATTR(1), xfs(5), EXT4(5)

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