File permissions on Linux determine how the operating system handles access requests for files and directories. There are three basic access permissions: read, write, and execute.
- Read permission (represented by "r" or the number 4) allows users to view the contents of a file.
- Write permission (represented by "w" or the number 2) allows users to modify the contents of a file.
- Execute permission (represented by "x" or the number 1) allows users to run executable files or access directories.
These permissions are set for three user groups: the owner of the file, the group to which the file belongs, and everyone else.
To determine the full permission settings for a file or directory, the access permissions and access types are combined. For example, a file with read and write permissions for the user would have a permissions value of 6 (4 + 2 = 6). If the file also has read permissions for the group and the world, the permissions values would be 4. So the total permissions value for the file would be represented numerically as 644.
When it comes to web servers and file permissions, it is important to ensure that the correct permissions are set for your website to function properly. HTML files and image files should be readable by others (the world) with a permission setting of 644. Directories should be executable by others with a permission setting of 755. CGI files in the cgi-bin directory should also be executable by others with a permission setting of 755.
To change the permissions for a file or directory, you can follow these steps:
- Log in to cPanel.
- Open the File Manager.
- Select the file or directory you want to change.
- Click on the Permissions icon:
- Set the correct permissions by checking the appropriate checkboxes.
- The numerical permission values will update automatically.
- Click on Change Permissions to apply the changes.
By understanding and correctly setting file permissions, you can ensure the security and proper functioning of your Linux system and web server.
