vagrant@precise32:/$ sudo -u logstash ls -la /var/log/logstash/
ls: cannot access /var/log/logstash/: Permission denied
vagrant@precise32:/$ ls -la /var/log/logstash/
total 8
drwxr-xr-x+  2 logstash logstash 4096 Jul 23 01:57 .
drwxr-xr-x+ 17 root     root     4096 Jul 23 01:57 ..
-rw-r--r--+  1 root     root        0 Jul 23 01:57 logstash.log