diff --git a/main.cpp b/main.cpp
index aed5285..2e79e2d 100644
--- a/main.cpp
+++ b/main.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <fcntl.h>
+#include <getopt.h>
 #include <poll.h>
 #include <unistd.h>
 
@@ -44,6 +45,8 @@
     }
 };
 
+static const char* snoopFilename = "/dev/aspeed-lpc-snoop0";
+
 /*
  * 256 bytes is a nice amount.  It's improbable we'd need this many, but its
  * gives us leg room in the event the driver poll doesn't return in a timely
@@ -65,6 +68,14 @@
     return;
 }
 
+static void usage(const char* name)
+{
+    fprintf(stderr,
+            "Usage: %s [-d <DEVICE>]\n"
+            "  -d, --device <DEVICE>  use <DEVICE> file. Default is '%s'\n\n",
+            name, snoopFilename);
+}
+
 /*
  * TODO(venture): this only listens one of the possible snoop ports, but
  * doesn't share the namespace.
@@ -75,6 +86,7 @@
 int main(int argc, char* argv[])
 {
     int rc = 0;
+    int opt;
     struct pollfd pollset;
     int pollr;
     int readb;
@@ -90,13 +102,27 @@
      */
     const char* snoopObject = SNOOP_OBJECTPATH;
     const char* snoopDbus = SNOOP_BUSNAME;
-    /*
-     * The following string would be promoted if used in another file under the
-     * same header.
-     */
-    auto snoopFilename = "/dev/aspeed-lpc-snoop0";
+
     bool deferSignals = true;
 
+    static const struct option long_options[] = {
+        {"device", required_argument, NULL, 'd'}, {0, 0, 0, 0}};
+
+    while ((opt = getopt_long(argc, argv, "d:", long_options, NULL)) != -1)
+    {
+        switch (opt)
+        {
+            case 0:
+                break;
+            case 'd':
+                snoopFilename = optarg;
+                break;
+            default:
+                usage(argv[0]);
+                exit(EXIT_FAILURE);
+        }
+    }
+
     postFd = open(snoopFilename, 0);
     if (postFd < 0)
     {