diff --git a/apps/dsm/DSMCoreModule.cpp b/apps/dsm/DSMCoreModule.cpp
index 866cad6d..6f540339 100644
--- a/apps/dsm/DSMCoreModule.cpp
+++ b/apps/dsm/DSMCoreModule.cpp
@@ -75,6 +75,7 @@ DSMAction* DSMCoreModule::getAction(const string& from_str) {
 
   DEF_CMD("set", SCSetAction);
   DEF_CMD("append", SCAppendAction);
+  DEF_CMD("substr", SCSubStrAction);
   DEF_CMD("inc", SCIncAction);
   DEF_CMD("log", SCLogAction);
   DEF_CMD("clear", SCClearAction);
@@ -351,6 +352,29 @@ EXEC_ACTION_START(SCAppendAction) {
       var_name.c_str(), sc_sess->var[var_name].c_str());
 } EXEC_ACTION_END;
 
+CONST_ACTION_2P(SCSubStrAction,',', false);
+EXEC_ACTION_START(SCSubStrAction) {
+  string var_name = (par1.length() && par1[0] == '$')?
+    par1.substr(1) : par1;
+  unsigned int pos = 0;
+  if (str2i(resolveVars(par2, sess, sc_sess, event_params), pos)) {
+    ERROR("substr length '%s'\n",
+	  resolveVars(par2, sess, sc_sess, event_params).c_str());
+    sc_sess->SET_ERRNO(DSM_ERRNO_UNKNOWN_ARG);
+    return false;
+  }
+  try {
+    sc_sess->var[var_name] = sc_sess->var[var_name].substr(pos);
+  } catch(...) {
+    ERROR("in substr\n");
+    sc_sess->SET_ERRNO(DSM_ERRNO_UNKNOWN_ARG);
+    return false;
+  }
+
+  DBG("$%s now '%s'\n", 
+      var_name.c_str(), sc_sess->var[var_name].c_str());
+} EXEC_ACTION_END;
+
 EXEC_ACTION_START(SCIncAction) {
   string var_name = (arg.length() && arg[0] == '$')?
     arg.substr(1) : arg;
diff --git a/apps/dsm/DSMCoreModule.h b/apps/dsm/DSMCoreModule.h
index fce60437..ecd9ebb0 100644
--- a/apps/dsm/DSMCoreModule.h
+++ b/apps/dsm/DSMCoreModule.h
@@ -76,6 +76,7 @@ DEF_SCModSEStrArgAction(SCReturnFSMAction);
 
 DEF_ACTION_2P(SCSetAction);
 DEF_ACTION_2P(SCAppendAction);
+DEF_ACTION_2P(SCSubStrAction);
 DEF_ACTION_1P(SCIncAction);
 DEF_ACTION_1P(SCClearAction);
 DEF_ACTION_2P(SCSetTimerAction);