It means absolute freedom. The Owner, Group, and Public can all Read, Write, and Execute the file. Warning: This is highly insecure and generally should not be used on web servers.

It means everyone can Read and Write the file, but nobody can Execute it as a program. (4 Read + 2 Write = 6). It is common for text files that multiple users need to edit.

The Owner has full control (7). The Group and Public can only Read and Execute (5). This is the standard, secure permission for directories and executable scripts.

The Owner can Read and Write (6). Everyone else can only Read (4). This is the standard, secure permission for basic files like HTML, CSS, or images on a web server.

The leading zero specifies special permission modes (SetUID, SetGID, and Sticky Bit). In most basic daily usage, `0755` functions identically to `755`.

Unlike a file where "execute" runs a script, "execute" on a directory allows a user to `cd` into it and access the files inside. Without execute, you cannot open the folder.

The string `-rwxr-xr-x` is broken down into chunks. The first character is the type (`-` for file, `d` for directory). The next three are Owner permissions, then Group, then Public.

Use the `-R` flag. For example, `chmod -R 755 folder_name` will apply the 755 permissions to the folder and every single file inside it.

The Owner is usually the user who created the file. You can change the owner of a file using the `chown` command.

This refers to any user on the system who is not the Owner and is not a member of the assigned Group. It is literally "everyone else."