ESL-77 your test script works along with single_command.rb now

libs/esl/ruby/Makefile

@@ -4,7 +4,7 @@ LOCAL_CFLAGS=$(shell ruby cflags.rb)
 all: ESL.so
 
 esl_wrap.cpp:
-	swig -module ESL -ruby -c++ -DMULTIPLICITY -I../src/include -o esl_wrap.cpp ../ESL.i
+	swig2.0 -module ESL -ruby -c++ -DMULTIPLICITY -I../src/include -o esl_wrap.cpp ../ESL.i
 
 esl_wrap.o: esl_wrap.cpp
 	$(CXX) $(CXX_CFLAGS) $(CXXFLAGS) $(LOCAL_CFLAGS) -c esl_wrap.cpp -o esl_wrap.o

libs/esl/ruby/single_command.rb

 #! /usr/bin/ruby
+require_relative './ESL' 
 
-require "ESL"
+HOST     = '127.0.0.1'.to_s 
+PORT     = '8021'.to_s 
+PASSWORD = 'ClueCon'.to_s 
 
 command = ARGV.join(" ")
-con = ESL::ESLconnection.new("localhost", "8021", "ClueCon")
-e = con.sendRecv("api #{command}")
-puts e.getBody()
+
+con = ESL::ESLconnection.new(HOST,PORT,PASSWORD) 
+e = con.sendRecv('api ' + command)
+
+puts e.getBody
+