nPrefix strings copied
to start of each block.
nUsed
to create uniqueness between hosts and/or devices/files.
nPrefix Format Control
Strings:
u%d = The device name. %D = The real device name.
u%h = The host name. %H = The full host name.
u%p = The process ID. %P = The parent PID.
u%u = The user name.
n Example:
prefix="%u@%h (pid %p)"