📰Day 6 - File Permissions and Access Control Lists

🔈File Permissions with Examples

Linux file permissions are used to control who can read, write, and execute a file. This is important because Linux systems are multi-user, and file permissions are a security mechanism that protects system files from users and viruses.

Mainly Linux has three types of file permissions:

Read (r): Allows a user or group to view a file.
Write (w): Allows a user to write or modify a file or directory.
Execute (x): Allows a user or group to execute a file or view a directory.

◼️How do you view Linux file permissions?

ls -l: The ls command along with its -l (for long listing) option will show you metadata about your Linux files, including the permissions set on the file.

Here is Some examples:

✔️Create a simple file and do ls -ltr to see the details of the files:

✔️owner — The owner of the file or application and If you want to change the ownership of a file and directory use "chown".
✔️group — The group that owns the file or application and To change the group permission of file and directory use "chgrp".
✔️To change the other users permissions of a file or directory used "chmod"

🔈Access Control List (ACL)

It is a mechanism for controlling access to file and directories on a Linux System. ACLs allows you to specify permissions for individual users and groups.
✔️To view the Access Control List for a file or directory, use getfacl command.

e.g. To view the ACLs for the file /etc/passwd
✔️To set or modify the Access Control List for a file or directory, use setfacl command.

e.g. To add the user newuser to the ACL for the file /etc/passwd with read and write permissions.

♻️Conclusion

Understanding file permissions and Access Control Lists (ACLs) is vital for securing computing environments. File permissions in Linux regulate access, while ACLs provide granular control.