__fish_print_{addresses,interfaces}: Add alternative to net_tools

net_tools, which provides `ifconfig` and `netstat`, among other things,
has last been updated in 2013. This means `ifconfig` on linux is
basically dead.

Instead of ifconfig, use `ip` (from iproute2), which is much more powerful and
provides a much more annoying commandline syntax.

Instead of netstat, just look at /sys/class/net.

share/functions/__fish_print_addresses.fish

@@ -1,4 +1,8 @@
 function __fish_print_addresses --description "Print a list of known network addresses"
-	/sbin/ifconfig | __fish_sgrep 'inet addr'|cut -d : -f 2|cut -d ' ' -f 1
+	if command -s ip >/dev/null
+		command ip --oneline address | cut -d" " -f7 | sed "s:\(.*\)/.*:\1:"
+	else if command -s ifconfig >/dev/null
+		command ifconfig |sgrep 'inet addr'|cut -d : -f 2|cut -d ' ' -f 1
+	end
 end
 

share/functions/__fish_print_interfaces.fish

@@ -1,3 +1,10 @@
 function __fish_print_interfaces --description "Print a list of known network interfaces"
-	netstat -i -n -a | awk 'NR>2'|awk '{print $1}'
+	if test -d /sys/class/net
+		cd /sys/class/net
+		for i in *
+			echo $i
+		end
+	else
+		netstat -i -n -a | awk 'NR>2'|awk '{print $1}'
+	end
 end