Sixth chapter Linux file permissions and directory configuration

(1) Type of file:

(i) ordinary documents (-);

(ii) Catalogue document (d);

(iii) connection file (L), similar to the WINDWOS system below the shortcut;

(iv) Equipment and equipment files: first, block equipment files, is some storage data to provide system random access to the interface device, such as hard disk, floppy disk;

Second, the character (character) device file, also is some serial port interface device, such as keyboard, mouse.

(v) Sockets (s), this type of file is usually used for data connections on the network;

(vi) Pipeline (fifo,pipe) (p), a special type of file, which is primarily intended to resolve errors caused by simultaneous access to a file by multiple programs.

Whether a Linux file can be executed is related to the 10 properties of its first column, which is not related to the file name at all. Of course, if the contents of the file cannot be executed, even if there is an X in the file's permissions, it cannot be executed.

(2) Change the properties and permissions of the file:

CHGRP: Change the user group that the file belongs to;

Chown: Change the file owner;

chmod: Change the permissions of the file.

For example: Chgrp bin text.c Change text.c user group to bin; Change bin owner and user group to Root:chown root:root text.c

(3) directory and file permissions meaning

(a) The permissions of the file is relatively simple: readable representation of the actual content of the file can be read, can be written to edit, add or modify the contents of the file, executable indicates that the file has permissions that can be executed by the system.

(ii) The importance of the permissions of the directory: for the readable, the right to read the directory structure list, you can use the "ls" command to display the table of contents of the directory; a readable representation has the right to change the directory structure list, to create new, delete, rename, or transfer files under the directory The executable represents whether the user can enter the directory as the working directory.

Note: If the permissions for a directory are drwxr--r--, members of the user group can only read the list of file names for that directory, but because there is no executable permission, the "LS" command displays "? ”。 Therefore, the General Web site administrator Open Directory data should be readable executable, but can not be read with the table, otherwise the general user can arbitrarily change the site data.

Sixth chapter Linux file permissions and directory configuration