How to Change File Permissions on Your WordPress Blog's Web Server
Every file and folder on your WordPress blog's web server has a set of assigned attributions, called permissions, that tells the web server three things about the folder or file. On a very simplistic level, these permissions include:
Read: This setting determines whether the file/folder is readable by the web server.
Write: This setting determines whether the file/folder is writable by the web server.
Execute: This setting determines whether the file/folder is executable by the web server.
Each set of permissions has a numeric code assigned to it, identifying what type of permissions are assigned to that file or folder. There are a lot of them, so here are the most common ones that you run into when running a WordPress website:
644: Files with permissions set to 644 are readable by everyone and writable only by the file/folder owner.
755: Files with permissions set to 755 are readable and executable by everyone, but they’re writable only by the file/folder owner.
777: Files with permissions set to 777 are readable, writable, and executable by everyone. For security reasons, you should not use this set of permissions on your web server unless absolutely necessary.
Typically, folders and files within your web server are assigned permissions of either 644 or 755. Usually, you’ll see PHP files, or files that end with the .php extension, with permissions set to 644 if the web server is configured to use PHP Safe Mode.
You may run across a situation where you’re asked to edit and change the file permissions on a particular file on your web server. With WordPress sites, this usually happens when dealing with plugins or theme files that require files or folders to be writable by the web server.
This practice is referred to as CHMOD, an acronym for Change Mode. When someone says, You need to CHMOD that file to 755, you’ll know what they are talking about.
Here are some easy steps for using your FTP program to CHMOD a file, or edit its permissions on your web server:
Connect the FTP client to your web server.
Locate the file you want to CHMOD.
Open the file attributes for the file.
Right-click the file on your web server and choose File Permissions. (Your FTP client, if not FileZilla, may use different terminology.)
The Change File Attributes window appears.
Type the correct file permissions number in the Numeric Value field.
This is the number assigned to the permissions you want to give the file. Most often, the plugin or theme developer tells you which permissions number to assign to the file or folder; typically, it will be either 644 or 755.
Click OK to save the file.