network mac adresses: ip support fix

lib/network.js

@@ -30,7 +30,7 @@ const _sunos = (_platform === 'sunos');
 let _network = {};
 let _default_iface;
 let _mac = {};
-let isIpAvailable;
+let pathToIp;
 
 function getDefaultNetworkInterface() {
 
@@ -72,19 +72,24 @@ function getMacAddresses() {
   let mac = '';
   let result = {};
   if (_linux || _freebsd || _openbsd) {
-    if (typeof isIpAvailable === 'undefined') {
-      if (fs.existsSync('/sbin/ip')) {
-        isIpAvailable = true;
-      } else {
-        isIpAvailable = false;
+    if (typeof pathToIp === 'undefined') {
+      try {
+        const lines = execSync('which ip').toString().split('\n');
+        if (lines.length && lines[0].indexOf(':') === -1 && lines[0].indexOf('/') === 0) {
+          pathToIp = lines[0];
+        } else {
+          pathToIp = '';
+        }
+      } catch (e) {
+        pathToIp = '';
       }
     }
-    const cmd = 'export LC_ALL=C; /sbin/' + ((isIpAvailable) ? 'ip link show up' : 'ifconfig') + '; unset LC_ALL';
+    const cmd = 'export LC_ALL=C; ' + ((pathToIp) ? pathToIp + ' link show up' : '/sbin/ifconfig') + '; unset LC_ALL';
     let res = execSync(cmd);
     const lines = res.toString().split('\n');
     for (let i = 0; i < lines.length; i++) {
       if (lines[i] && lines[i][0] !== ' ') {
-        if (isIpAvailable) {
+        if (pathToIp) {
           let nextline = lines[i + 1].trim().split(' ');
           if (nextline[0] === 'link/ether') {
             iface = lines[i].split(' ')[1];