Day 6 :- File Permissions and Access control list.

Today is more on Reading, Learning and Implementing File permissions.

The concept of Linux File permission and ownership is important in Linux. Here, we will be working on Linux permissions and ownership and will do tasks on both of them.

In Linux, file permissions and Access Control Lists (ACLs) are crucial mechanisms for managing access to files and directories. They help ensure security and control over who can read, write, or execute files.

File Permissions:

File permissions in Linux are represented by three sets of characters: owner permissions, group permissions, and others permissions.

Owner permissions (u): These permissions apply to the user who owns the file.
Group permissions (g): These permissions apply to the group associated with the file.
Others permissions (o): These permissions apply to everyone else.

Each set of permissions consists of three characters, which can be:

r (read): Permission to read the file or list the directory's contents.
w (write): Permission to modify the file or add/remove files in the directory.
x (execute): Permission to execute the file or traverse the directory.

For example, rwxr-x--- represents read, write, and execute permissions for the owner, read and execute permissions for the group, and no permissions for others.

Changing File Permissions:

You can modify file permissions using the chmod command, followed by the permission mode and the filename.

Example:

bashCopy codechmod u+x filename

Access Control Lists (ACLs):

ACLs extend the standard Unix file permission system by providing a finer level of control. With ACLs, you can define permissions for specific users and groups beyond the owner and group associated with the file.

ACLs are managed using the setfacl and getfacl commands.

setfacl: Used to set ACLs for files and directories.
getfacl: Used to display ACLs for files and directories.

Example of Using ACLs:

Suppose you want to give user "user1" read and write permissions to a file:

Copy codesetfacl -m u:user1:rw filename

This command adds read and write permissions for "user1" to the file.

Combining Standard Permissions and ACLs:

Standard permissions and ACLs can work together. ACLs allow you to grant additional permissions without changing the standard permissions.

Summary:

File Permissions: Standard Unix permissions managed with chmod.
Access Control Lists (ACLs): Provide finer-grained access control beyond standard permissions, managed with setfacl and getfacl.
Both mechanisms work together to control access to files and directories in Linux.

Day 6 :- File Permissions and Access Control Lists.