diff --git a/Operand.cpp b/Operand.cpp
index 3d6f44e..ca4c94f 100644
--- a/Operand.cpp
+++ b/Operand.cpp
@@ -124,9 +124,26 @@ namespace jet {
 	 } else
 	   throw coreutils::Exception("Expecting ) at end of TOLOWER expression.");	 	 	 	 	 
       } else if(in.ifNextIgnoreCase("REVERSE")) {
-	 
+	 if(!in.ifNext("("))
+	   throw coreutils::Exception("Expecting ( for REVERSE parameters.");
+	 Operand parm1(in, tag);
+	 if(in.ifNext(")")) {
+	    std::string reversed = parm1.string.str();
+	    std::reverse(reversed.begin(), reversed.end());
+	    string = reversed;
+	 } else
+	   throw coreutils::Exception("Expecting ) at end of REVERSE expression.");
       } else if(in.ifNextIgnoreCase("CONCAT")) {
-	 
+	 if(!in.ifNext("("))
+	   throw coreutils::Exception("Expecting ( for CONCAT parameters.");
+	 Operand parm1(in, tag);
+	 string = parm1.string;
+	 while(in.ifNext(",")) {
+	    Operand parm(in, tag);
+	    string << parm.string;
+	 }
+	 if(!in.ifNext(")"))
+	   throw coreutils::Exception("Expecting ) at end of CONCAT expression.");
       } else if(in.ifNextIgnoreCase("INTEGER")) {
 	 if(!in.ifNext("("))
 	   throw coreutils::Exception("Expecting ( for INTEGER parameters.");