This section describes publicly accessible networking
utilities in alphabetical order.
Upon termination each command returns two bytes of status,
one supplied by the system giving the cause for
termination, and (in the case of ``normal'' termination)
one supplied by the program, see
The former byte is 0 for normal termination, the latter is
customarily 0 for successful execution, nonzero to indicate
troubles such as erroneous parameters, bad or inaccessible
data, or other inability to cope with the task at hand. It
is called variously ``exit code'', ``exit status'' or
``return code'', and is described only where special
conventions are involved.