Unix file types

Regular file                                                                                     Main article: Computer file

-rw-r-—r-- ... /etc/passwd

Directory                                                                                         Main article: File directory

drwxr-xr-x 26 root root 4096 Sep 22 09:29 /

Symbolic link                                                                                  Main article: Symbolic link

lrwxrwxrwx ... termcap -> /usr/share/misc/termcap

Named pipe                                                                                    Main article: Named pipe

prw-rw---- ... mypipe

Socket                                                              Main article: Unix domain socket

A socket is a special file used for inter-process communication.

These allow communication between two processes.

In addition to sending data, processes can send file descriptors

across a Unix domain socket connection

using the sendmsg() and recvmsg() system calls.

Unlike named pipes sockets are fully duplex-capable.

srwxrwxrwx ... /tmp/.X11-unix/X0

Device file                                                                                         Main article: Device file

Device files are used to apply access rights and to direct operations on the files to the appropriate device drivers.

Unix makes a distinction between character devices and block devices. The distinction is roughly as follows:

• character devices provide only a serial stream of input or output;
• block devices are randomly accessible;

crw------- ... /dev/null brw-rw---- ... /dev/sda

Door                                                                                                   Main article: Doors (computing)

A door is a special file for inter-process communication between a client and server, currently implemented in the Sun Solaris operating system only.

Dr--r--r-- ... name_service_door

from:http://en.wikipedia.org/wiki/Unix_file_type