Add systemd-cat example

Author: wjoel

examples/systemd-cat.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+log_level="info"
+if [ "$MESOS_LOG_STREAM" = "STDERR" ]; then
+  log_level="err"
+fi
+
+task_id=$(echo "$MESOS_EXECUTORINFO_JSON" | \
+  jq -r '.command.environment.variables[]|select(.name=="MESOS_TASK_ID").value')
+
+if [ "$task_id" ]; then
+    task_identifier="-t $task_id"
+fi
+
+systemd-cat $task_identifier -p $log_level