diff --git a/src/fluka/app/mainFluDAG.cpp b/src/fluka/app/mainFluDAG.cpp
index a011244088..fd0f5bfa34 100644
--- a/src/fluka/app/mainFluDAG.cpp
+++ b/src/fluka/app/mainFluDAG.cpp
@@ -13,6 +13,7 @@
 #include "dagmcmetadata.hpp"
 #include "moab/ProgOptions.hpp"
 
+#include <cstdlib>
 #include <cstring>
 #include <fstream>
 #include <time.h>       // for timing the routine
@@ -116,8 +117,30 @@ int main(int argc, char* argv[]) {
     fludag_write_ididx(vol_id);
   } else {
     // call fluka run
-    // flugg mode is flag = 1
-    const int flag = 1;
+    
+    // check for the input file argument
+    // get it from the command line
+    if(argc >= 1) {
+      // convert to std::string
+      std::string chinpf_s(argv[1]);
+      char chinpf[256] = "";
+      memset(chinpf,' ',256);
+      std::copy(chinpf_s.begin(),chinpf_s.end(),chinpf);
+      strcpy(chcmpt_.chinpf,chinpf);
+    } else {
+      // get it from the environment
+      std::cout << "from env" << std::endl;
+      char* env = std::getenv("INPF");
+      std::cout << env << std::endl;
+      strncpy(env,chcmpt_.chinpf,sizeof(env));
+      if (chcmpt_.chinpf[0] == 0) {
+	//	flabrt("FLUKAM","FLUDAG NO INPUT SPECIFIED");
+	return 1;
+      }
+      std::cout << chcmpt_.chinpf << std::endl;
+    }
+    const int flag = 2;
+    std::cout << "running fluka" << std::endl;
     flukam(flag);
   }
 
diff --git a/src/fluka/fluka_funcs.h b/src/fluka/fluka_funcs.h
index 50492a2df6..b52a4e6a00 100644
--- a/src/fluka/fluka_funcs.h
+++ b/src/fluka/fluka_funcs.h
@@ -132,6 +132,24 @@ extern "C" {
   } mulbou_;
 }
 
+// the CHCMPT struct for
+// setting the input name
+extern "C" {
+  extern struct {
+    char comptr[50];
+    char inpfil[200];
+    char pwddir[200];
+    char hlfdir[200];
+    char homdir[200];
+    char hostnm[200];
+    char usrflk[200];
+    char grpflk[200];
+    char inpnam[200];
+    char chinpf[256];
+    char hfpath[200];
+  } chcmpt_;
+}
+
 // struct to hold particle state
 struct particle_state {
   moab::DagMC::RayHistory history;