Linux File Permissions

Three types of access:

• Read - Denoted as r, files with read access can be displayed to the user.
• Write - Denoted as w, files with write access can be modified by the user.
• Execute - Denoted as x, files with execute access can be executed as programs by the user.

Three types of user group:

• User - The owner of the file.
• Group - Other files which are in the same folder or group.
• World - Everyone else.

The web server needs to be able to read your web pages in order to be able to display them in a browser. The following permissions need to be set in order for your web site to function properly.

• All HTML files and images need to be readable by others. The value for this is 644 (readable by User, Group and World, and writable by User). It is set automatically when you upload files.
• All folders need to be executable by others. The value for this is 755 (readable by User, Group and World, writable by User, executable by User, Group and World). It is set automatically when you create a folder.
• All CGI files (all files in the cgi-bin folder) need to be executable by other. The value for this is 755 (readable by User, Group, and World, writable by User, executable by User, Group, and World). It is not set automatically when you upload files. You need to change file permissions manually.

It is important that none of your files or folders is writable by anyone else. Any file or folder which is writable by others can be erased by them.