why “ls -al” does not show file size info in /dev/socket directory?

Question

In /dev/socket directory, if runs "ls -al" in adb, there is no file size information. I would like to know why there is no such information, in the condition that in other directories can show file size information?

Thanks.

Answer 1

Sockets and pipes represent Unix' way of inter process communication, and a communication channel has no point in having a size. Sockets are thus not seekable as in go to position x in the file.

Linux (which Android makes use of) has 7 file types:

• Regular Files
• Directories
• Character  Device Files
• Block Device Files
• Local Domain Sockets
• Named Pipes
• Symbolic Links

See more here