Linux General Concepts
Internal
Processes
A process is an operating system level construct that holds all the resources an application maintains and uses at runtime. These resources include, but are not limited to a memory address space, file handles, devices and threads.
Signals
Sockets
Unix domain sockets are bidirectional communication mechanisms that allow processes running within the same host operation system to exchange data. IP (network) sockets are bidirectional communication mechanisms allowing processes running on different hosts to exchange data over the network. Because of simplifying assumptions, UNIX sockets are faster and lighter, so they should be preferred over network sockets when we are sure the process are collocated. UNIX and network sockets share the API. They are subject to filesystem permissions. More details: https://en.wikipedia.org/wiki/Unix_domain_socket, https://en.wikipedia.org/wiki/Network_socket.