add new one-liner to 'awk' section

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -3259,6 +3259,15 @@ awk '!x[$0]++' filename
 awk '{print $NF}' filename
 ```
 
+###### Remove empty lines
+
+```bash
+awk 'NF > 0' filename
+
+# alternative:
+awk NF filename
+```
+
 ###### Print multiple columns with separators
 
 ```bash