Fix /proc/net/tcp* check in InternalCommandPortListeningCheck t… (#2195)

Author: perlun

core/src/main/java/org/testcontainers/containers/wait/internal/InternalCommandPortListeningCheck.java

@@ -29,7 +29,7 @@ public Boolean call() {
         for (int internalPort : internalPorts) {
             command += " && ";
             command += " (";
-            command += format("cat /proc/net/tcp{,6} | awk '{print $2}' | grep -i :%x", internalPort);
+            command += format("cat /proc/net/tcp* | awk '{print $2}' | grep -i :%x", internalPort);
             command += " || ";
             command += format("nc -vz -w 1 localhost %d", internalPort);
             command += " || ";

core/src/test/java/org/testcontainers/containers/wait/internal/InternalCommandPortListeningCheckTest.java

@@ -11,8 +11,8 @@
 
 public class InternalCommandPortListeningCheckTest {
 
-    // Linking a custom configuration into the container so that nginx is listening on port 8080. This is necessary to proof
-    // that the command formatting uses the correct casing for hexadecimal numberd (i.e. 1F90 and not 1f90).
+    // Linking a custom configuration into the container so that nginx is listening on port 8080. This is necessary to prove
+    // that the command formatting uses the correct casing for hexadecimal numbers (i.e. 1F90 and not 1f90).
     @Rule
     public GenericContainer nginx = new GenericContainer<>("nginx:1.9.4")
             .withClasspathResourceMapping("nginx_on_8080.conf", "/etc/nginx/conf.d/default.conf", BindMode.READ_ONLY);