Today is more on Reading, Learning and Implementing File permissions
File permissions and access control lists are important concepts in Linux that control access to files and directories.
File Permissions:
In Linux, file permission refers to the level of access or permission granted to a file or directory for a particular user or group of users. Linux provides three types of permissions for a file or directory: read, write, and execute. These permissions are assigned to three groups of users: owner, group, and others.
Read permission allows a user to view the contents of a file or directory
Write permission allows a user to modify the contents of a file or directory
Execute permission allows a user to execute a file or access a directory
Each group can have one of three levels of permission: allow, deny, or no permission. These permissions are represented by the letters r, w, and x respectively.
For example, if a file has the following permissions:
-rw-r--r--
In this example, the first character -
indicates that this is a regular file. The next three characters rw-
indicate that the owner of the file has read and write permissions, but not execute permissions. The next three characters r--
indicate that the group that the file belongs to has read permissions, but not write or execute permissions. The final three characters r--
indicate that all other users on the system have read permissions, but do not write or execute permissions.
To change file permissions, you can use the chmod
command followed by the permissions you want to set and the name of the file. For example, to give the owner of the file file1.txt
execute permissions, you could use the following command:
chmod u+x file1.txt
In this command, u
represents the owner of the file, +
indicates that you are adding permission, and x
indicates that you are adding execute permissions.
Access Control List:
In addition to file permissions, Linux also supports Access Control Lists (ACLs) to provide more fine-grained control over access to files and directories. ACLs allow you to define specific permissions for individual users and groups beyond the traditional owner, group, and other permissions.
ACLs are represented by a list of entries that specify the user or group and the permissions granted to them. For example, an ACL entry might look like this:
user:binod:rwx
This entry grants user "binod" read, write, and execute permissions.
ACLs are more complex than traditional file permissions, but they offer greater flexibility and granularity for controlling access to files and directories.
In conclusion, file permissions and access control lists are important concepts in Linux that control access to files and directories. Understanding how to use them effectively is essential for ensuring the security and privacy of your data.