file permission experience

srwxrwxrwx 1 root root 0 Apr 2 13:29 X0
srwxrwxrwx 1 root root 0 Apr 2 13:23 X1
srwxrwxrwx 1 root root 0 Apr 2 13:23 X2
srwxrwxrwx 1 root root 0 Apr 2 13:23 X3
srwxrwxrwx 1 root root 0 Apr 2 13:26 X4
srwxrwxrwx 1 root root 0 Apr 2 13:27 X5
srwxrwxrwx 1 root root 0 Apr 2 13:29 X6
srwxrwxrwx 1 root root 0 Apr 2 13:31 X7

here first character "s" means socket

There are some other bits in the Linux File permission
* setuid
-rwsrwxrwt

* setgid
-rwxrwsrwt

* sticky bit
drwxrwxrwt

How to change the special file permission?
# chmod 0700 file-name clean all the special permission bits
# chmod 1700 file-name set setuid bit
# chmod 2700 file-name set setgid bit
# chmod 4700 file-name set sticky bit