If I run netstat --all | grep ^unix some of the socket paths that are outputted are preceded with a '@' and some aren't. I've noticed that those preceded with a '@' don't show up when browsing the file system with ls but the rest do.What are these two kinds of sockets and what is the difference between them?
Can someone explain the different types of unix domain sockets?
socket
These are abstract sockets, that live outside the filesystem namespace.  netstat --unix, lsof -U and other commands print an @ sign instead of the nul byte that's at the start of the pathname.