Error: unknown command "ko" for "kubectl"

For issue #652

dist/images/install.sh

@@ -2186,6 +2186,14 @@ chmod +x /usr/local/bin/kubectl-ko
 echo "-------------------------------"
 echo ""
 
+echo $PATH | grep '/usr/local/bin'
+if [  $? != 0  ]; then
+  echo "Tips:Please join the /usr/local/bin to your PATH. Temporarily, we do it for this execution."
+  export PATH=/usr/local/bin:$PATH
+  echo "-------------------------------"
+  echo ""
+fi
+
 echo "[Step 6] Run network diagnose"
 kubectl ko diagnose all