spawn package:xmonad-contrib is:module

Provides a way to modify a window spawned by a command(e.g shift it to the workspace it was launched on) by using the _NET_WM_PID property that most windows set on creation. Hence this module won't work on applications that don't set this property.
A module for spawning a pipe whose Handle lives in the Xmonad state.
A module for spawning a command once, and only once. Useful to start status bars and make session settings inside startupHook. See also SessionStart for a different and more flexible way to run commands only on first startup.