The following table lists and describes the permissions that you can give to each class of user for a file or directory.
Table 7–2 File and Directory Permissions
Symbol |
Permission |
Object |
Description |
---|---|---|---|
r |
Read |
File |
Designated users can open and read the contents of a file. |
|
|
Directory |
Designated users can list files in the directory. |
w |
Write |
File |
Designated users can modify the contents of the file or delete the file. |
|
|
Directory |
Designated users can add files or add links in the directory. They can also remove files or remove links in the directory. |
x |
Execute |
File |
Designated users can execute the file, if it is a program or shell script. They also can run the program with one of the exec(2) system calls. |
|
|
Directory |
Designated users can open files or execute files in the directory. They also can make the directory and the directories beneath it current. |
- |
Denied |
File and Directory |
Designated users cannot read, write, or execute the file. |
These file permissions apply to regular files, and to special files such as devices, sockets, and named pipes (FIFOs).
For a symbolic link, the permissions that apply are the permissions of the file that the link points to.
You can protect the files in a directory and its subdirectories by setting restrictive file permissions on that directory. Note, however, that superuser has access to all files and directories on the system.