Terminate the awk after getting the first interface name and IP address
from 'ip -4 addr' output. Otherwise, the test fails if the interface
in question has multiple IP addresses, as the test program returns
the first address, while awk prints all.
Fall back to getting the interface name from 'ip -4 addr' when there
is no default route. In this case, the test simply uses the interface
providing the IP address for 'ip -4 addr' (since the command is
implicitly called with no interface argument).
Michał Górny
yangfl
Thomas Bernard