diff --git a/slsDetectorServers/slsDetectorServer/src/slsDetectorServer.c b/slsDetectorServers/slsDetectorServer/src/slsDetectorServer.c
index d6c39d082..df17a5518 100644
--- a/slsDetectorServers/slsDetectorServer/src/slsDetectorServer.c
+++ b/slsDetectorServers/slsDetectorServer/src/slsDetectorServer.c
@@ -152,12 +152,12 @@ int main(int argc, char *argv[]) {
             strcpy(version, APIXILINXCTB);
 #endif
             LOG(logINFO, ("SLS Detector Server Version: %s\n", version));
-            exit(EXIT_SUCCESS);
+            return EXIT_SUCCESS;
 
         case 'p':
             if (sscanf(optarg, "%d", &portno) != 1) {
                 LOG(logERROR, ("Cannot scan port argument\n%s", helpMessage));
-                exit(EXIT_FAILURE);
+                return EXIT_FAILURE;
             }
             LOG(logINFO, ("Detected port: %d\n", portno));
             break;
@@ -188,7 +188,7 @@ int main(int argc, char *argv[]) {
             ignoreConfigFileFlag = 1;
 #else
             LOG(logERROR, ("No server config files for this detector\n"));
-            exit(EXIT_FAILURE);
+            return EXIT_FAILURE;
 #endif
             break;
 
@@ -196,11 +196,11 @@ int main(int argc, char *argv[]) {
 #if !defined(VIRTUAL) && !defined(EIGERD)
             LOG(logERROR, ("Cannot set master via the detector server for this "
                            "detector\n"));
-            exit(EXIT_FAILURE);
+            return EXIT_FAILURE;
 #elif defined(GOTTHARD2D) || defined(EIGERD) || defined(MYTHEN3D)
             if (sscanf(optarg, "%d", &masterCommandLine) != 1) {
                 LOG(logERROR, ("Cannot scan master argument\n%s", helpMessage));
-                exit(EXIT_FAILURE);
+                return EXIT_FAILURE;
             }
             if (masterCommandLine == 1) {
                 LOG(logINFO, ("Detector Master mode\n"));
@@ -209,7 +209,7 @@ int main(int argc, char *argv[]) {
             }
 #else
             LOG(logERROR, ("No master implemented for this detector server\n"));
-            exit(EXIT_FAILURE);
+            return EXIT_FAILURE;
 #endif
             break;
 
@@ -217,7 +217,7 @@ int main(int argc, char *argv[]) {
 #ifdef EIGERD
             if (sscanf(optarg, "%d", &topCommandLine) != 1) {
                 LOG(logERROR, ("Cannot scan top argument\n%s", helpMessage));
-                exit(EXIT_FAILURE);
+                return EXIT_FAILURE;
             }
             if (topCommandLine == 1) {
                 LOG(logINFO, ("Detector Top mode\n"));
@@ -226,16 +226,16 @@ int main(int argc, char *argv[]) {
             }
 #else
             LOG(logERROR, ("No top implemented for this detector server\n"));
-            exit(EXIT_FAILURE);
+            return EXIT_FAILURE;
 #endif
             break;
 
         case 'h':
             printf("%s", helpMessage);
-            exit(EXIT_SUCCESS);
+            return EXIT_SUCCESS;
         default:
             printf("\n%s", helpMessage);
-            exit(EXIT_FAILURE);
+            return EXIT_FAILURE;
         }
     }
 
@@ -376,5 +376,5 @@ int main(int argc, char *argv[]) {
 #endif
     }
     LOG(logINFO, ("Goodbye!\n"));
-    return 0;
+    return EXIT_SUCCESS;
 }
diff --git a/slsDetectorSoftware/src/CmdApp.cpp b/slsDetectorSoftware/src/CmdApp.cpp
index facb584a8..946b4f9c2 100644
--- a/slsDetectorSoftware/src/CmdApp.cpp
+++ b/slsDetectorSoftware/src/CmdApp.cpp
@@ -84,7 +84,7 @@ int main(int argc, char *argv[]) {
         c.call(parser.command(), parser.arguments(), parser.detector_id(),
                action, std::cout, parser.receiver_id());
     } catch (sls::RuntimeError &e) {
-        exit(EXIT_FAILURE);
+        return EXIT_FAILURE;
     }
-    exit(EXIT_SUCCESS);
+    return EXIT_SUCCESS;
 }
\ No newline at end of file
diff --git a/slsReceiverSoftware/CMakeLists.txt b/slsReceiverSoftware/CMakeLists.txt
index 543ff7467..46d80970b 100755
--- a/slsReceiverSoftware/CMakeLists.txt
+++ b/slsReceiverSoftware/CMakeLists.txt
@@ -13,6 +13,7 @@ set(SOURCES
     src/Arping.cpp
     src/MasterAttributes.cpp
     src/MasterFileUtility.cpp
+    src/CommandLineOptions.cpp
 )
 
 set(PUBLICHEADERS
@@ -51,6 +52,10 @@ target_link_libraries(slsReceiverObject
     slsProjectWarnings #don't propagate warnigns 
 )
 
+target_compile_definitions(slsReceiverObject 
+    PRIVATE $<$<BOOL:${SLS_USE_TESTS}>:SLS_USE_TESTS>
+)
+
 # HDF5
 if (SLS_USE_HDF5)
     if (HDF5_FOUND)
@@ -86,6 +91,7 @@ set_target_properties(slsReceiverStatic PROPERTIES
     ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin
     PUBLIC_HEADER "${PUBLICHEADERS}"
 )
+
 list(APPEND RECEIVER_LIBRARY_TARGETS slsReceiverStatic)
 
 
diff --git a/slsReceiverSoftware/include/sls/Receiver.h b/slsReceiverSoftware/include/sls/Receiver.h
index eb7c4b214..0a3a83482 100644
--- a/slsReceiverSoftware/include/sls/Receiver.h
+++ b/slsReceiverSoftware/include/sls/Receiver.h
@@ -13,22 +13,12 @@ class Receiver : private virtual slsDetectorDefs {
   public:
     /**
      * Constructor
-     * Starts up a Receiver server. Reads configuration file, options, and
-     * assembles a Receiver using TCP and UDP detector interfaces
+     * Starts up a Receiver server.
+     * Assembles a Receiver using TCP and UDP detector interfaces
      * throws an exception in case of failure
-     * @param argc from command line
-     * @param argv from command line
+     * @param port TCP/IP port number
      */
-    Receiver(int argc, char *argv[]);
-
-    /**
-     * Constructor
-     * Starts up a Receiver server. Reads configuration file, options, and
-     * assembles a Receiver using TCP and UDP detector interfaces
-     * throws an exception in case of failure
-     * @param tcpip_port_no TCP/IP port number
-     */
-    Receiver(uint16_t tcpip_port_no = 1954);
+    Receiver(uint16_t port = 1954);
 
     ~Receiver();
 
diff --git a/slsReceiverSoftware/src/CommandLineOptions.cpp b/slsReceiverSoftware/src/CommandLineOptions.cpp
new file mode 100644
index 000000000..517b591fd
--- /dev/null
+++ b/slsReceiverSoftware/src/CommandLineOptions.cpp
@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+
+#include "CommandLineOptions.h"
+#include "sls/ToString.h"
+#include "sls/logger.h"
+#include "sls/sls_detector_defs.h"
+#include "sls/versionAPI.h"
+
+#include <cstring>
+#include <unistd.h>
+
+CommandLineOptions::CommandLineOptions(AppType app)
+    : appType_(app), optString_(buildOptString()),
+      longOptions_(buildOptionList()) {}
+
+/** for testing */
+ParsedOptions CommandLineOptions::parse(const std::vector<std::string> &args) {
+    std::vector<char *> argv;
+    argv.reserve(args.size());
+    for (const auto &arg : args) {
+        argv.push_back(const_cast<char *>(arg.c_str()));
+    }
+    int argc = static_cast<int>(argv.size());
+    return parse(argc, argv.data());
+}
+
+ParsedOptions CommandLineOptions::parse(int argc, char *argv[]) {
+    CommonOptions base;
+    MultiReceiverOptions multi;
+    FrameSyncOptions frame;
+    base.port = DEFAULT_TCP_RX_PORTNO;
+
+    optind = 0; // reset getopt
+    int opt, option_index = 0;
+
+    while ((opt = getopt_long(argc, argv, optString_.c_str(),
+                              longOptions_.data(), &option_index)) != -1) {
+        switch (opt) {
+        case 'v':
+        case 'h':
+            handleCommonOption(opt, optarg, base);
+            return base; // exit after version/help
+        case 'p':
+        case 'u':
+            handleCommonOption(opt, optarg, base);
+            break;
+        case 'c':
+        case 'n':
+        case 't':
+            handleAppSpecificOption(opt, optarg, base, multi, frame);
+            break;
+        default:
+            throw sls::RuntimeError("Invalid arguments." + getHelpMessage());
+        }
+    }
+
+    // remaining arguments
+    if (optind < argc) {
+
+        // deprecated and current options => invalid
+        if (base.port != DEFAULT_TCP_RX_PORTNO || multi.numReceivers != 1 ||
+            frame.numReceivers != 1 || multi.callbackEnabled != false ||
+            frame.printHeaders != false) {
+            LOG(sls::logWARNING) << "Cannot use both deprecated options and "
+                                    "the valid options simultaneously. Please "
+                                    "move away from the deprecated options.\n";
+        }
+
+        // unsupported deprecated arguments
+        if (appType_ == AppType::SingleReceiver) {
+            throw sls::RuntimeError("Invalid arguments." + getHelpMessage());
+        }
+
+        // parse deprecated arguments
+        std::vector<std::string> args(argv, argv + argc);
+        auto [p, n, o] = ParseDeprecated(args);
+        // set options
+        base.port = p;
+        if (appType_ == AppType::MultiReceiver) {
+            multi.numReceivers = n;
+            multi.callbackEnabled = o;
+        } else if (appType_ == AppType::FrameSynchronizer) {
+            frame.numReceivers = n;
+            frame.printHeaders = o;
+        }
+    }
+
+    // Logging
+    LOG(sls::logINFO) << "TCP Port: " << base.port;
+    if (appType_ == AppType::MultiReceiver) {
+        LOG(sls::logINFO) << "Number of receivers: " << multi.numReceivers;
+        LOG(sls::logINFO) << "Callback enabled: " << multi.callbackEnabled;
+    } else if (appType_ == AppType::FrameSynchronizer) {
+        LOG(sls::logINFO) << "Number of receivers: " << frame.numReceivers;
+        LOG(sls::logINFO) << "Print headers: " << frame.printHeaders;
+    }
+
+    switch (appType_) {
+    case AppType::SingleReceiver:
+        return base;
+    case AppType::MultiReceiver:
+        static_cast<CommonOptions &>(multi) = base;
+        return multi;
+    case AppType::FrameSynchronizer:
+        static_cast<CommonOptions &>(frame) = base;
+        return frame;
+    default:
+        throw sls::RuntimeError("Unknown AppType in CommandLineOptions::parse");
+    }
+}
+
+std::vector<option> CommandLineOptions::buildOptionList() const {
+    std::vector<option> opts = {
+        {"version", no_argument, nullptr, 'v'},
+        {"help", no_argument, nullptr, 'h'},
+        {"port", required_argument, nullptr, 'p'},
+        {"uid", required_argument, nullptr, 'u'},
+    };
+    switch (appType_) {
+    case AppType::SingleReceiver:
+        opts.push_back({"rx_tcpport", required_argument, nullptr, 't'});
+        break;
+    case AppType::MultiReceiver:
+        opts.push_back({"num-receivers", required_argument, nullptr, 'n'});
+        opts.push_back({"callback", no_argument, nullptr, 'c'});
+        break;
+    case AppType::FrameSynchronizer:
+        opts.push_back({"num-receivers", required_argument, nullptr, 'n'});
+        opts.push_back({"print-headers", no_argument, nullptr, 'c'});
+        break;
+    }
+    opts.push_back({nullptr, 0, nullptr, 0}); // null-terminator for getopt
+    return opts;
+}
+
+std::string CommandLineOptions::buildOptString() const {
+    std::string optstr = "vhp:u:";
+    if (appType_ == AppType::MultiReceiver ||
+        appType_ == AppType::FrameSynchronizer)
+        optstr += "cn:";
+    if (appType_ == AppType::SingleReceiver)
+        optstr += "t:";
+    return optstr;
+}
+
+uint16_t CommandLineOptions::parsePort(const char *optarg) {
+    uint16_t val = 0;
+    try {
+        val = sls::StringTo<uint16_t>(optarg);
+    } catch (...) {
+        throw sls::RuntimeError("Could not parse port number " +
+                                std::string(optarg));
+    }
+    if (val < 1024) {
+        throw sls::RuntimeError(
+            "Invalid/ privileged port number parsed. Min: 1024.");
+    }
+    return val;
+}
+
+uint16_t CommandLineOptions::parseNumReceivers(const char *optarg) {
+    uint16_t val = 0;
+    try {
+        val = sls::StringTo<uint16_t>(optarg);
+    } catch (...) {
+        throw sls::RuntimeError("Could not parse number of receivers " +
+                                std::string(optarg));
+    }
+    if (val == 0 || val > MAX_RECEIVERS) {
+        throw sls::RuntimeError(
+            "Invalid number of receivers parsed. Options: 1 - " +
+            std::to_string(MAX_RECEIVERS));
+    }
+    return val;
+}
+
+uid_t CommandLineOptions::parseUID(const char *optarg) {
+    uid_t val = -1;
+    try {
+        val = sls::StringTo<uid_t>(optarg);
+    } catch (...) {
+        throw sls::RuntimeError("Could not parse UID " + std::string(optarg));
+    }
+    if (val == static_cast<uid_t>(-1)) {
+        throw sls::RuntimeError(
+            "Could not parse UID. Expected a valid user ID." +
+            std::string(optarg));
+    }
+    return val;
+}
+
+void CommandLineOptions::handleCommonOption(int opt, const char *optarg,
+                                            CommonOptions &base) {
+    switch (opt) {
+    case 'v':
+        base.versionRequested = true;
+        std::cout << getVersion() << std::endl;
+        break;
+    case 'h':
+        base.helpRequested = true;
+        std::cout << getHelpMessage() << std::endl;
+        break;
+    case 'p':
+        base.port = parsePort(optarg);
+        break;
+    case 'u':
+        base.userid = parseUID(optarg);
+        setEffectiveUID(base.userid);
+        break;
+    }
+}
+
+void CommandLineOptions::handleAppSpecificOption(int opt, const char *optarg,
+                                                 CommonOptions &base,
+                                                 MultiReceiverOptions &multi,
+                                                 FrameSyncOptions &frame) {
+    switch (opt) {
+
+    case 'c':
+        if (appType_ == AppType::MultiReceiver)
+            multi.callbackEnabled = true;
+        else if (appType_ == AppType::FrameSynchronizer)
+            frame.printHeaders = true;
+        break;
+
+    case 'n': {
+        auto val = parseNumReceivers(optarg);
+        if (appType_ == AppType::MultiReceiver)
+            multi.numReceivers = val;
+        else if (appType_ == AppType::FrameSynchronizer)
+            frame.numReceivers = val;
+        break;
+    }
+
+    case 't':
+        LOG(sls::logWARNING) << "Deprecated option '-t' and '--rx_tcport'. Use "
+                                "'p' or '--port' instead.";
+        base.port = parsePort(optarg);
+        break;
+    }
+}
+
+/* maintain backward compatibility of [start port] [num receivers] [optional
+ * arg] */
+std::tuple<uint16_t, uint16_t, bool>
+CommandLineOptions::ParseDeprecated(const std::vector<std::string> &args) {
+
+    size_t nargs = args.size();
+    if (nargs != 1 && nargs != 3 && nargs != 4) {
+        throw sls::RuntimeError("Invalid number of arguments.");
+    }
+
+    LOG(sls::logWARNING)
+        << "Deprecated options will be removed in future versions. "
+           "Please use the new options.\n";
+
+    // default deprecated values
+    if (nargs == 1) {
+        return std::make_tuple(DEFAULT_TCP_RX_PORTNO, 1, false);
+    }
+
+    // parse deprecated arguments
+    uint16_t p = parsePort(args[1].c_str());
+    uint16_t n = parseNumReceivers(args[2].c_str());
+    bool o = false;
+    if (nargs == 4) {
+        try {
+            o = sls::StringTo<bool>(args[3].c_str());
+        } catch (...) {
+            throw sls::RuntimeError("Invalid optional argument "
+                                    "parsed. Expected 1 (true) or "
+                                    "0 (false).");
+        }
+    }
+    return std::make_tuple(p, n, o);
+}
+
+std::string CommandLineOptions::getTypeString() const {
+    switch (appType_) {
+    case AppType::SingleReceiver:
+        return "slsReceiver";
+    case AppType::MultiReceiver:
+        return "slsMultiReceiver";
+    case AppType::FrameSynchronizer:
+        return "slsFrameSynchronizer";
+    default:
+        return "Unknown";
+    }
+}
+
+std::string CommandLineOptions::getVersion() const {
+    return getTypeString() + " Version: " + APIRECEIVER;
+}
+
+std::string CommandLineOptions::getHelpMessage() const {
+    switch (appType_) {
+    case AppType::SingleReceiver:
+        return std::string("\nUsage: ") + getTypeString() + " Options:\n" +
+               "\t-v, --version       : Version.\n" +
+               "\t-p, --port          : TCP port to communicate with client "
+               "for "
+               "configuration. Non-zero and 16 bit.\n" +
+               "\t-u, --uid           : Set effective user id if receiver "
+               "started "
+               "with privileges. \n\n";
+
+    case AppType::MultiReceiver:
+        return std::string("\nUsage: " + getTypeString() + " Options:\n") +
+               "\t-v, --version       : Version.\n" +
+               "\t-n, --num-receivers : Number of receivers.\n" +
+               "\t-p, --port          : TCP port to communicate with client "
+               "for "
+               "configuration. Non-zero and 16 bit.\n" +
+               "\t-c, --callback      : Enable dummy callbacks for debugging. "
+               "Disabled by default. \n" +
+               "\t-u, --uid           : Set effective user id if receiver "
+               "started "
+               "with privileges. \n\n";
+
+    case AppType::FrameSynchronizer:
+        return std::string("\nUsage: " + getTypeString() + " Options:\n") +
+               "\t-v, --version       : Version.\n" +
+               "\t-n, --num-receivers : Number of receivers.\n" +
+               "\t-p, --port          : TCP port to communicate with client "
+               "for "
+               "configuration. Non-zero and 16 bit.\n" +
+               "\t-c, --print-headers : Print callback headers for debugging. "
+               "Disabled by default.\n" +
+               "\t-u, --uid           : Set effective user id if receiver "
+               "started "
+               "with privileges. \n\n";
+    }
+    throw sls::RuntimeError("Unknown AppType for help message");
+}
+
+void CommandLineOptions::setEffectiveUID(uid_t uid) {
+    if (geteuid() == uid) {
+        LOG(sls::logINFO) << "Process already has the same Effective UID "
+                          << uid;
+    } else {
+        if (seteuid(uid) != 0 || geteuid() != uid) {
+            throw sls::RuntimeError("Could not set Effective UID");
+        }
+        LOG(sls::logINFO) << "Process Effective UID changed to " << uid;
+    }
+}
\ No newline at end of file
diff --git a/slsReceiverSoftware/src/CommandLineOptions.h b/slsReceiverSoftware/src/CommandLineOptions.h
new file mode 100644
index 000000000..fbdaa01a4
--- /dev/null
+++ b/slsReceiverSoftware/src/CommandLineOptions.h
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+#pragma once
+
+#include <cstdint>
+#include <getopt.h>
+#include <string>
+#include <tuple>
+#include <variant>
+#include <vector>
+
+enum class AppType { MultiReceiver, SingleReceiver, FrameSynchronizer };
+
+struct CommonOptions {
+    uint16_t port = -1;
+    uid_t userid = -1;
+    bool versionRequested = false;
+    bool helpRequested = false;
+};
+
+struct MultiReceiverOptions : CommonOptions {
+    uint16_t numReceivers = 1;
+    bool callbackEnabled = false;
+};
+
+struct FrameSyncOptions : CommonOptions {
+    uint16_t numReceivers = 1;
+    bool printHeaders = false;
+};
+
+using ParsedOptions =
+    std::variant<CommonOptions, MultiReceiverOptions, FrameSyncOptions>;
+
+class CommandLineOptions {
+  public:
+    explicit CommandLineOptions(AppType app);
+    ParsedOptions parse(const std::vector<std::string> &args); // for testing
+    ParsedOptions parse(int argc, char *argv[]);
+    std::string getTypeString() const;
+    std::string getVersion() const;
+    std::string getHelpMessage() const;
+    static void setEffectiveUID(uid_t uid);
+    static std::tuple<uint16_t, uint16_t, bool>
+    ParseDeprecated(const std::vector<std::string> &args);
+
+  private:
+    AppType appType_;
+    std::string optString_;
+    std::vector<option> longOptions_;
+    std::vector<option> buildOptionList() const;
+    std::string buildOptString() const;
+
+    static uint16_t parsePort(const char *optarg);
+    static uint16_t parseNumReceivers(const char *optarg);
+    static uid_t parseUID(const char *optarg);
+    void handleCommonOption(int opt, const char *optarg, CommonOptions &base);
+    void handleAppSpecificOption(int opt, const char *optarg,
+                                 CommonOptions &base,
+                                 MultiReceiverOptions &multi,
+                                 FrameSyncOptions &frame);
+
+    static constexpr uint16_t MAX_RECEIVERS = 1000;
+};
diff --git a/slsReceiverSoftware/src/FrameSynchronizerApp.cpp b/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
index 4fc6c39fe..fc48814a9 100644
--- a/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
+++ b/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
@@ -5,16 +5,17 @@
  * reconstructing image. Sample python script for pull socket for this combiner
  * in python/scripts folder. TODO: Not handling empty frames from one socket
  */
+#include "CommandLineOptions.h"
 #include "sls/Receiver.h"
 #include "sls/ToString.h"
 #include "sls/container_utils.h"
 #include "sls/logger.h"
+#include "sls/network_utils.h"
 #include "sls/sls_detector_defs.h"
 
 #include <csignal> //SIGINT
 #include <cstdio>
 #include <cstring>
-#include <iostream>
 #include <mutex>
 #include <ostream>
 #include <semaphore.h>
@@ -28,9 +29,14 @@
 #include <zmq.h>
 
 std::vector<std::thread> threads;
-std::vector<sem_t *> semaphores;
 sls::TLogLevel printHeadersLevel = sls::logDEBUG;
 
+// gettid added in glibc 2.30
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
+#include <sys/syscall.h>
+#define gettid() syscall(SYS_gettid)
+#endif
+
 /** Define Colors to print data call back in different colors for different
  * recievers */
 #define PRINT_IN_COLOR(c, f, ...)                                              \
@@ -57,16 +63,6 @@ struct FrameStatus {
 };
 FrameStatus *global_frame_status = nullptr;
 
-/**
- * Control+C Interrupt Handler
- * to let all the processes know to exit properly
- */
-void sigInterruptHandler(int p) {
-    for (size_t i = 0; i != semaphores.size(); ++i) {
-        sem_post(semaphores[i]);
-    }
-}
-
 void cleanup() {
     if (global_frame_status) {
         std::lock_guard<std::mutex> lock(global_frame_status->mtx);
@@ -86,19 +82,6 @@ void cleanup() {
     }
 }
 
-/**
- * prints usage of this example program
- */
-std::string getHelpMessage() {
-    std::ostringstream os;
-    os << "\nUsage:\n"
-          "./slsFrameSynchronizer [start tcp port] [num recevers] [print "
-          "callback headers (optional)]\n"
-       << "\t - tcp port has to be non-zero and 16 bit\n"
-       << "\t - print callback headers option is 0 (disabled) by default\n";
-    return os.str();
-}
-
 void zmq_free(void *data, void *hint) { delete[] static_cast<char *>(data); }
 
 void print_frames(const PortFrameMap &frame_port_map) {
@@ -512,83 +495,46 @@ void GetDataCallback(slsDetectorDefs::sls_receiver_header &header,
     sem_post(&stat->available);
 }
 
+std::vector<sem_t> semaphores;
+
 /**
- * Example of main program using the Receiver class
- *
- * - Defines in file for:
- *  	- Default Number of receivers is 1
- *  	- Default Start TCP port is 1954
+ * Control+C Interrupt Handler
+ * to let all the processes know to exit properly
+ * Only the main thread will call this handler
  */
+void sigInterruptHandler(int p) {
+    (void)signal; // suppress unused warning if needed
+    for (auto &s : semaphores) {
+        sem_post(&s);
+    }
+}
+
 int main(int argc, char *argv[]) {
-
-    /**	- set default values */
-    int numReceivers = 1;
-    uint16_t startTCPPort = DEFAULT_TCP_RX_PORTNO;
-    bool printHeaders = false;
-
-    /**	- get number of receivers and start tcp port from command line
-     * arguments */
-    if (argc > 1) {
-        try {
-            if (argc == 3 || argc == 4) {
-                startTCPPort = sls::StringTo<uint16_t>(argv[1]);
-                if (startTCPPort == 0) {
-                    throw std::runtime_error("Invalid start tcp port");
-                }
-                numReceivers = std::stoi(argv[2]);
-                if (numReceivers > 1024) {
-                    cprintf(RED,
-                            "Did you mix up the order of the arguments?\n%s\n",
-                            getHelpMessage().c_str());
-                    return EXIT_FAILURE;
-                }
-                if (numReceivers == 0) {
-                    cprintf(RED, "Invalid number of receivers.\n%s\n",
-                            getHelpMessage().c_str());
-                    return EXIT_FAILURE;
-                }
-                if (argc == 4) {
-                    printHeaders = sls::StringTo<bool>(argv[3]);
-                    if (printHeaders) {
-                        printHeadersLevel = sls::logINFOBLUE;
-                    }
-                }
-            } else
-                throw std::runtime_error("Invalid number of arguments");
-        } catch (const std::exception &e) {
-            cprintf(RED, "Error: %s\n%s\n", e.what(), getHelpMessage().c_str());
-            return EXIT_FAILURE;
-        }
+    CommandLineOptions cli(AppType::FrameSynchronizer);
+    ParsedOptions opts;
+    try {
+        opts = cli.parse(argc, argv);
+    } catch (sls::RuntimeError &e) {
+        return EXIT_FAILURE;
+    }
+    auto &f = std::get<FrameSyncOptions>(opts);
+    if (f.versionRequested || f.helpRequested) {
+        return EXIT_SUCCESS;
     }
 
-    cprintf(RESET, "Number of Receivers: %d\n", numReceivers);
-    cprintf(RESET, "Start TCP Port: %hu\n", startTCPPort);
-    cprintf(RESET, "Print Callback Headers: %s\n\n",
-            (printHeaders ? "Enabled" : "Disabled"));
+    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << gettid() << ']';
 
-    /** - Catch signal SIGINT to close files and call destructors properly */
-    struct sigaction sa;
-    sa.sa_flags = 0;                     // no flags
-    sa.sa_handler = sigInterruptHandler; // handler function
-    sigemptyset(&sa.sa_mask); // dont block additional signals during invocation
-                              // of handler
-    if (sigaction(SIGINT, &sa, nullptr) == -1) {
-        cprintf(RED, "Could not set handler function for SIGINT\n");
+    // close files on ctrl+c
+    sls::setupSignalHandler(SIGINT, sigInterruptHandler);
+    // handle locally on socket crash
+    sls::setupSignalHandler(SIGPIPE, SIG_IGN);
+
+    semaphores.resize(f.numReceivers);
+    for (auto &s : semaphores) {
+        sem_init(&s, 0, 0);
     }
 
-    /** - Ignore SIG_PIPE, prevents global signal handler, handle locally,
-       instead of a server crashing due to client crash when writing, it just
-       gives error */
-    struct sigaction asa;
-    asa.sa_flags = 0;          // no flags
-    asa.sa_handler = SIG_IGN;  // handler function
-    sigemptyset(&asa.sa_mask); // dont block additional signals during
-                               // invocation of handler
-    if (sigaction(SIGPIPE, &asa, nullptr) == -1) {
-        cprintf(RED, "Could not set handler function for SIGPIPE\n");
-    }
-
-    FrameStatus stat{true, false, numReceivers};
+    FrameStatus stat{true, false, f.numReceivers};
     // store pointer for signal handler
     global_frame_status = &stat;
 
@@ -596,34 +542,44 @@ int main(int argc, char *argv[]) {
     void *user_data = static_cast<void *>(&stat);
     std::thread combinerThread(Correlate, &stat);
 
-    for (int i = 0; i != numReceivers; ++i) {
-        sem_t *semaphore = new sem_t;
-        sem_init(semaphore, 1, 0);
-        semaphores.push_back(semaphore);
+    std::exception_ptr threadException = nullptr;
+    for (int i = 0; i != f.numReceivers; ++i) {
+        uint16_t port = f.port + i;
+        sem_t *semaphore = &semaphores[i];
+        threads.emplace_back(
+            [i, semaphore, port, user_data, &threadException]() {
+                LOG(sls::logINFOBLUE)
+                    << "Thread " << i << " [ Tid: " << gettid() << ']';
+                try {
+                    sls::Receiver receiver(port);
+                    receiver.registerCallBackStartAcquisition(
+                        StartAcquisitionCallback, user_data);
+                    receiver.registerCallBackAcquisitionFinished(
+                        AcquisitionFinishedCallback, user_data);
+                    receiver.registerCallBackRawDataReady(GetDataCallback,
+                                                          user_data);
 
-        uint16_t port = startTCPPort + i;
-        threads.emplace_back([i, semaphore, port, user_data]() {
-            sls::Receiver receiver(port);
-            receiver.registerCallBackStartAcquisition(StartAcquisitionCallback,
-                                                      user_data);
-            receiver.registerCallBackAcquisitionFinished(
-                AcquisitionFinishedCallback, user_data);
-            receiver.registerCallBackRawDataReady(GetDataCallback, user_data);
-            /**	- as long as no Ctrl+C */
-            sem_wait(semaphore);
-            sem_destroy(semaphore);
-            delete semaphore;
-
-            // clean up frames
-            if (i == 0)
-                cleanup();
-        });
+                    /**	- as long as no Ctrl+C */
+                    // each child shares the common semaphore
+                    sem_wait(semaphore);
+                } catch (...) {
+                    // capture exception and raise SIGINT to exit gracefully
+                    threadException = std::current_exception();
+                    raise(SIGINT);
+                }
+                LOG(sls::logINFOBLUE)
+                    << "Exiting Thread " << i << " [ Tid: " << gettid() << " ]";
+            });
     }
 
-    for (auto &thread : threads) {
-        thread.join();
+    for (auto &t : threads) {
+        t.join();
     }
 
+    for (auto &s : semaphores)
+        sem_destroy(&s);
+    cleanup();
+
     {
         std::lock_guard<std::mutex> lock(stat.mtx);
         stat.terminate = true;
@@ -632,6 +588,19 @@ int main(int argc, char *argv[]) {
     combinerThread.join();
     sem_destroy(&stat.available);
 
+    if (threadException) {
+        try {
+            std::rethrow_exception(threadException);
+        } catch (const std::exception &e) {
+            LOG(sls::logERROR)
+                << "Unhandled exception from thread: " << e.what();
+            return EXIT_FAILURE;
+        } catch (...) {
+            LOG(sls::logERROR) << "Unknown exception occurred in thread";
+            return EXIT_FAILURE;
+        }
+    }
+
     LOG(sls::logINFOBLUE) << "Goodbye!";
     return EXIT_SUCCESS;
 }
diff --git a/slsReceiverSoftware/src/MultiReceiverApp.cpp b/slsReceiverSoftware/src/MultiReceiverApp.cpp
index 44284281c..a1bc4cb83 100644
--- a/slsReceiverSoftware/src/MultiReceiverApp.cpp
+++ b/slsReceiverSoftware/src/MultiReceiverApp.cpp
@@ -2,15 +2,16 @@
 // Copyright (C) 2021 Contributors to the SLS Detector Package
 /* Creates the slsMultiReceiver for running multiple receivers form a single
  * binary */
+#include "CommandLineOptions.h"
 #include "sls/Receiver.h"
 #include "sls/ToString.h"
 #include "sls/container_utils.h"
 #include "sls/logger.h"
+#include "sls/network_utils.h"
 #include "sls/sls_detector_defs.h"
 
 #include <csignal> //SIGINT
 #include <cstring>
-#include <iostream>
 #include <semaphore.h>
 #include <sys/wait.h> //wait
 #include <unistd.h>
@@ -26,28 +27,6 @@
 #define PRINT_IN_COLOR(c, f, ...)                                              \
     printf("\033[%dm" f RESET, 30 + c + 1, ##__VA_ARGS__)
 
-sem_t semaphore;
-
-/**
- * Control+C Interrupt Handler
- * to let all the processes know to exit properly
- */
-void sigInterruptHandler(int p) { sem_post(&semaphore); }
-
-/**
- * prints usage of this example program
- */
-std::string getHelpMessage() {
-    std::ostringstream os;
-    os << "\nUsage:\n"
-       << "./slsMultiReceiver [start tcp port] [num recevers] [call back "
-          "option (optional)]\n"
-       << "\t - tcp port has to be non-zero and 16 bit\n"
-       << "\t - call back option is 0 (disabled) by default, 1 prints frame "
-          "header for debugging\n";
-    return os.str();
-}
-
 /**
  * Start Acquisition Call back (slsMultiReceiver writes data if file write
  * enabled) if registerCallBackRawDataReady or
@@ -146,99 +125,48 @@ void GetData(slsDetectorDefs::sls_receiver_header &header,
         // header->packetsMask.to_string().c_str(),
         ((uint8_t)(*((uint8_t *)(dataPointer)))), imageSize);
 
-    // // example of how to use roi or modify data that is later written to file
-    // slsDetectorDefs::ROI roi{0, 10, 0, 20};
-    // int width = roi.xmax - roi.xmin;
-    // int height = roi.ymax - roi.ymin;
-    // uint8_t *destPtr = (uint8_t *)dataPointer;
-    // for (int irow = roi.ymin; irow < roi.ymax; ++irow) {
-    //     memcpy(destPtr,
-    //            ((uint8_t *)(dataPointer + irow * callbackHeader.shape.x +
-    //                         roi.xmin)),
-    //            width);
-    //     destPtr += width;
-    // }
-    // memcpy((uint8_t*)dataPointer, (uint8_t*)dataPointer
-    // // setting roi for eg. changes size
-    // imageSize = width * height;
+    // if data is modified, can affect size
+    // only reduction in size allowed, not increase
+    // imageSize = 26000;
 }
 
+sem_t semaphore;
+
 /**
- * Example of main program using the Receiver class
- *
- * - Defines in file for:
- *  	- Default Number of receivers is 1
- *  	- Default Start TCP port is 1954
+ * Control+C Interrupt Handler
+ * to let all the processes know to exit properly
+ * All child processes will call the handler (parent process set to ignore)
  */
+void sigInterruptHandler(int signal) {
+    (void)signal; // suppress unused warning if needed
+    sem_post(&semaphore);
+}
+
 int main(int argc, char *argv[]) {
 
-    /**	- set default values */
-    int numReceivers = 1;
-    uint16_t startTCPPort = DEFAULT_TCP_RX_PORTNO;
-    int withCallback = 0;
+    CommandLineOptions cli(AppType::MultiReceiver);
+    ParsedOptions opts;
+    try {
+        opts = cli.parse(argc, argv);
+    } catch (sls::RuntimeError &e) {
+        return EXIT_FAILURE;
+    }
+    auto &m = std::get<MultiReceiverOptions>(opts);
+    if (m.versionRequested || m.helpRequested) {
+        return EXIT_SUCCESS;
+    }
+
+    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << gettid() << ']';
+
+    // close files on ctrl+c
+    sls::setupSignalHandler(SIGINT, sigInterruptHandler);
+    // handle locally on socket crash
+    sls::setupSignalHandler(SIGPIPE, SIG_IGN);
+
     sem_init(&semaphore, 1, 0);
 
-    /**	- get number of receivers and start tcp port from command line
-     * arguments */
-    if (argc > 1) {
-        try {
-            if (argc == 3 || argc == 4) {
-                startTCPPort = sls::StringTo<uint16_t>(argv[1]);
-                if (startTCPPort == 0) {
-                    throw std::runtime_error("Invalid start tcp port");
-                }
-                numReceivers = std::stoi(argv[2]);
-                if (numReceivers > 1024) {
-                    cprintf(RED,
-                            "Did you mix up the order of the arguments?\n%s\n",
-                            getHelpMessage().c_str());
-                    return EXIT_FAILURE;
-                }
-                if (numReceivers == 0) {
-                    cprintf(RED, "Invalid number of receivers.\n%s\n",
-                            getHelpMessage().c_str());
-                    return EXIT_FAILURE;
-                }
-                if (argc == 4) {
-                    withCallback = std::stoi(argv[3]);
-                }
-            } else
-                throw std::runtime_error("Invalid number of arguments");
-        } catch (const std::exception &e) {
-            cprintf(RED, "Error: %s\n%s\n", e.what(), getHelpMessage().c_str());
-            return EXIT_FAILURE;
-        }
-    }
-
-    cprintf(BLUE, "Parent Process Created [ Tid: %ld ]\n", (long)gettid());
-    cprintf(RESET, "Number of Receivers: %d\n", numReceivers);
-    cprintf(RESET, "Start TCP Port: %hu\n", startTCPPort);
-    cprintf(RESET, "Callback Enable: %d\n", withCallback);
-
-    /** - Catch signal SIGINT to close files and call destructors properly */
-    struct sigaction sa;
-    sa.sa_flags = 0;                     // no flags
-    sa.sa_handler = sigInterruptHandler; // handler function
-    sigemptyset(&sa.sa_mask); // dont block additional signals during invocation
-                              // of handler
-    if (sigaction(SIGINT, &sa, nullptr) == -1) {
-        cprintf(RED, "Could not set handler function for SIGINT\n");
-    }
-
-    /** - Ignore SIG_PIPE, prevents global signal handler, handle locally,
-       instead of a server crashing due to client crash when writing, it just
-       gives error */
-    struct sigaction asa;
-    asa.sa_flags = 0;          // no flags
-    asa.sa_handler = SIG_IGN;  // handler function
-    sigemptyset(&asa.sa_mask); // dont block additional signals during
-                               // invocation of handler
-    if (sigaction(SIGPIPE, &asa, nullptr) == -1) {
-        cprintf(RED, "Could not set handler function for SIGPIPE\n");
-    }
-
-    /** - loop over number of receivers */
-    for (int i = 0; i < numReceivers; ++i) {
+    /** - loop over receivers */
+    for (int i = 0; i < m.numReceivers; ++i) {
 
         /**	- fork process to create child process */
         pid_t pid = fork();
@@ -246,86 +174,89 @@ int main(int argc, char *argv[]) {
         /**	- if fork failed, raise SIGINT and properly destroy all child
          * processes */
         if (pid < 0) {
-            cprintf(RED, "fork() failed. Killing all the receiver objects\n");
+            LOG(sls::logERROR)
+                << "fork() failed. Killing all the receiver objects";
             raise(SIGINT);
         }
 
         /**	- if child process */
         else if (pid == 0) {
-            cprintf(BLUE, "Child process %d [ Tid: %ld ]\n", i, (long)gettid());
+            LOG(sls::logINFOBLUE)
+                << "Child process " << i << " [ Tid: " << gettid() << ']';
 
-            std::unique_ptr<sls::Receiver> receiver = nullptr;
             try {
-                receiver = sls::make_unique<sls::Receiver>(startTCPPort + i);
+                uint16_t port = m.port + i;
+                sls::Receiver receiver(port);
+
+                /**	- register callbacks. remember to set file write enable
+                 * to 0 (using the client) if we should not write files and you
+                 * will write data using the callbacks */
+                if (m.callbackEnabled) {
+
+                    /** - Call back for start acquisition */
+                    LOG(sls::logINFOBLUE) << "Registering StartAcq()";
+                    receiver.registerCallBackStartAcquisition(StartAcq,
+                                                              nullptr);
+
+                    /** - Call back for acquisition finished */
+                    LOG(sls::logINFOBLUE)
+                        << "Registering AcquisitionFinished()";
+                    receiver.registerCallBackAcquisitionFinished(
+                        AcquisitionFinished, nullptr);
+
+                    /* 	- Call back for raw data */
+                    LOG(sls::logINFOBLUE) << "Registering GetData()";
+                    receiver.registerCallBackRawDataReady(GetData, nullptr);
+                }
+
+                /**	- as long as no Ctrl+C */
+                // each child process gets a copy of the semaphore
+                sem_wait(&semaphore);
+                sem_destroy(&semaphore);
+                LOG(sls::logINFOBLUE)
+                    << "Exiting Child Process [ Tid: " << gettid() << ']';
+                exit(EXIT_SUCCESS);
             } catch (...) {
+                sem_destroy(&semaphore);
                 LOG(sls::logINFOBLUE)
                     << "Exiting Child Process [ Tid: " << gettid() << " ]";
-                throw;
+                exit(EXIT_FAILURE);
             }
-            /**	- register callbacks. remember to set file write enable to 0
-             * (using the client) if we should not write files and you will
-             * write data using the callbacks */
-            if (withCallback) {
-
-                /** - Call back for start acquisition */
-                cprintf(BLUE, "Registering StartAcq()\n");
-                receiver->registerCallBackStartAcquisition(StartAcq, nullptr);
-
-                /** - Call back for acquisition finished */
-                cprintf(BLUE, "Registering AcquisitionFinished()\n");
-                receiver->registerCallBackAcquisitionFinished(
-                    AcquisitionFinished, nullptr);
-
-                /* 	- Call back for raw data */
-                cprintf(BLUE, "Registering GetData() \n");
-                receiver->registerCallBackRawDataReady(GetData, nullptr);
-            }
-
-            /**	- as long as no Ctrl+C */
-            sem_wait(&semaphore);
-            sem_destroy(&semaphore);
-            cprintf(BLUE, "Exiting Child Process [ Tid: %ld ]\n",
-                    (long)gettid());
-            exit(EXIT_SUCCESS);
-            break;
         }
     }
 
-    /** - Parent process ignores SIGINT (exits only when all child process
-     * exits) */
-    sa.sa_flags = 0;          // no flags
-    sa.sa_handler = SIG_IGN;  // handler function
-    sigemptyset(&sa.sa_mask); // dont block additional signals during invocation
-                              // of handler
-    if (sigaction(SIGINT, &sa, nullptr) == -1) {
-        cprintf(RED, "Could not set handler function for SIGINT\n");
-    }
+    /** - Parent process ignores SIGINT and waits for all the child processes to
+     * handle the signal */
+    sls::setupSignalHandler(SIGINT, SIG_IGN);
 
     /** - Print Ready and Instructions how to exit */
     std::cout << "Ready ... \n";
-    cprintf(RESET, "\n[ Press \'Ctrl+c\' to exit ]\n");
+    LOG(sls::logINFO) << "\n[ Press \'Ctrl+c\' to exit ]";
 
     /** - Parent process waits for all child processes to exit */
     for (;;) {
-        pid_t childPid = waitpid(-1, nullptr, 0);
+        int status;
+        pid_t childPid = waitpid(-1, &status, 0);
 
         // no child closed
         if (childPid == -1) {
             if (errno == ECHILD) {
-                cprintf(GREEN, "All Child Processes have been closed\n");
+                LOG(sls::logINFOGREEN)
+                    << "All Child Processes have been closed";
                 break;
             } else {
-                cprintf(RED, "Unexpected error from waitpid(): (%s)\n",
-                        strerror(errno));
+                LOG(sls::logERROR)
+                    << "Unexpected error from waitpid(): " << strerror(errno);
                 break;
             }
         }
 
-        // child closed
-        cprintf(BLUE, "Exiting Child Process [ Tid: %ld ]\n",
-                (long int)childPid);
+        if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
+            std::cerr << "Child " << childPid << " failed\n";
+            kill(0, SIGINT); // signal other children to exit
+        }
     }
 
     std::cout << "Goodbye!\n";
-    return 0;
+    return EXIT_SUCCESS;
 }
diff --git a/slsReceiverSoftware/src/Receiver.cpp b/slsReceiverSoftware/src/Receiver.cpp
index d2d5593d5..c9a299b19 100644
--- a/slsReceiverSoftware/src/Receiver.cpp
+++ b/slsReceiverSoftware/src/Receiver.cpp
@@ -27,106 +27,14 @@ namespace sls {
 
 Receiver::~Receiver() = default;
 
-Receiver::Receiver(int argc, char *argv[]) : tcpipInterface(nullptr) {
-
-    // options
-    uint16_t tcpip_port_no = 1954;
-    uid_t userid = -1;
-
-    // parse command line for config
-    static struct option long_options[] = {
-        // These options set a flag.
-        //{"verbose", no_argument,       &verbose_flag, 1},
-        // These options don’t set a flag. We distinguish them by their indices.
-        {"rx_tcpport", required_argument, nullptr,
-         't'}, // TODO change or backward compatible to "port, p"?
-        {"uid", required_argument, nullptr, 'u'},
-        {"version", no_argument, nullptr, 'v'},
-        {"help", no_argument, nullptr, 'h'},
-        {nullptr, 0, nullptr, 0}};
-
-    // initialize global optind variable (required when instantiating multiple
-    // receivers in the same process)
-    optind = 1;
-    // getopt_long stores the option index here.
-    int option_index = 0;
-    int c = 0;
-
-    std::string help_message =
-        "\nUsage: " + std::string(argv[0]) + " [arguments]\n" +
-        "Possible arguments are:\n" +
-        "\t-t, --rx_tcpport <port> : TCP Communication Port with "
-        "client. Non-zero and 16 bit.\n" +
-        "\t-u, --uid <user id>     : Set effective user id if receiver "
-        "\n" +
-        "\t                          started with privileges. \n\n";
-
-    while (c != -1) {
-        c = getopt_long(argc, argv, "hvf:t:u:", long_options, &option_index);
-
-        // Detect the end of the options.
-        if (c == -1)
-            break;
-
-        switch (c) {
-
-        case 't':
-            try {
-                tcpip_port_no = sls::StringTo<uint16_t>(optarg);
-                validatePortNumber(tcpip_port_no);
-            } catch (...) {
-                throw RuntimeError("Could not scan TCP port number." +
-                                   help_message);
-            }
-            break;
-
-        case 'u':
-            if (sscanf(optarg, "%u", &userid) != 1) {
-                throw RuntimeError("Could not scan uid" + help_message);
-            }
-            break;
-
-        case 'v':
-            std::cout << "SLS Receiver Version: " << APIRECEIVER << std::endl;
-            LOG(logINFOBLUE) << "Exiting [ Tid: " << gettid() << " ]";
-            exit(EXIT_SUCCESS);
-
-        case 'h':
-            std::cout << help_message << std::endl;
-            exit(EXIT_SUCCESS);
-        default:
-            throw RuntimeError(help_message);
-        }
+Receiver::Receiver(uint16_t port) {
+    validatePortNumber(port);
+#ifdef SLS_USE_TESTS
+    if (port == 65535) {
+        throw sls::RuntimeError("Throwing for testing purposes. ");
     }
-
-    // set effective id if provided
-    if (userid != static_cast<uid_t>(-1)) {
-        if (geteuid() == userid) {
-            LOG(logINFO) << "Process already has the same Effective UID "
-                         << userid;
-        } else {
-            if (seteuid(userid) != 0) {
-                std::ostringstream oss;
-                oss << "Could not set Effective UID to " << userid;
-                throw RuntimeError(oss.str());
-            }
-            if (geteuid() != userid) {
-                std::ostringstream oss;
-                oss << "Could not set Effective UID to " << userid << ". Got "
-                    << geteuid();
-                throw RuntimeError(oss.str());
-            }
-            LOG(logINFO) << "Process Effective UID changed to " << userid;
-        }
-    }
-
-    // might throw an exception
-    tcpipInterface = make_unique<ClientInterface>(tcpip_port_no);
-}
-
-Receiver::Receiver(uint16_t tcpip_port_no) {
-    // might throw an exception
-    tcpipInterface = make_unique<ClientInterface>(tcpip_port_no);
+#endif
+    tcpipInterface = make_unique<ClientInterface>(port);
 }
 
 std::string Receiver::getReceiverVersion() {
diff --git a/slsReceiverSoftware/src/ReceiverApp.cpp b/slsReceiverSoftware/src/ReceiverApp.cpp
index 767339869..92ff84b50 100644
--- a/slsReceiverSoftware/src/ReceiverApp.cpp
+++ b/slsReceiverSoftware/src/ReceiverApp.cpp
@@ -1,9 +1,12 @@
 // SPDX-License-Identifier: LGPL-3.0-or-other
 // Copyright (C) 2021 Contributors to the SLS Detector Package
 /* slsReceiver */
+#include "CommandLineOptions.h"
 #include "sls/Receiver.h"
+#include "sls/ToString.h"
 #include "sls/container_utils.h"
 #include "sls/logger.h"
+#include "sls/network_utils.h"
 #include "sls/sls_detector_defs.h"
 
 #include <csignal> //SIGINT
@@ -18,44 +21,49 @@
 
 sem_t semaphore;
 
-void sigInterruptHandler(int p) { sem_post(&semaphore); }
+/**
+ * Control+C Interrupt Handler
+ * to let all the other process know to exit properly
+ */
+void sigInterruptHandler(int signal) {
+    (void)signal; // suppress unused warning if needed
+    sem_post(&semaphore);
+}
 
 int main(int argc, char *argv[]) {
 
+    CommandLineOptions cli(AppType::SingleReceiver);
+    ParsedOptions opts;
+    try {
+        opts = cli.parse(argc, argv);
+    } catch (sls::RuntimeError &e) {
+        return EXIT_FAILURE;
+    }
+    auto &o = std::get<CommonOptions>(opts);
+    if (o.versionRequested || o.helpRequested) {
+        return EXIT_SUCCESS;
+    }
+
+    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << gettid() << " ]";
+
+    // close files on ctrl+c
+    sls::setupSignalHandler(SIGINT, sigInterruptHandler);
+    // handle locally on socket crash
+    sls::setupSignalHandler(SIGPIPE, SIG_IGN);
+
     sem_init(&semaphore, 1, 0);
 
-    LOG(sls::logINFOBLUE) << "Created [ Tid: " << gettid() << " ]";
-
-    // Catch signal SIGINT to close files and call destructors properly
-    struct sigaction sa;
-    sa.sa_flags = 0;                     // no flags
-    sa.sa_handler = sigInterruptHandler; // handler function
-    sigemptyset(&sa.sa_mask); // dont block additional signals during invocation
-                              // of handler
-    if (sigaction(SIGINT, &sa, nullptr) == -1) {
-        LOG(sls::logERROR) << "Could not set handler function for SIGINT";
-    }
-
-    // if socket crash, ignores SISPIPE, prevents global signal handler
-    // subsequent read/write to socket gives error - must handle locally
-    struct sigaction asa;
-    asa.sa_flags = 0;          // no flags
-    asa.sa_handler = SIG_IGN;  // handler function
-    sigemptyset(&asa.sa_mask); // dont block additional signals during
-                               // invocation of handler
-    if (sigaction(SIGPIPE, &asa, nullptr) == -1) {
-        LOG(sls::logERROR) << "Could not set handler function for SIGPIPE";
-    }
-
     try {
-        sls::Receiver r(argc, argv);
+        sls::Receiver r(o.port);
         LOG(sls::logINFO) << "[ Press \'Ctrl+c\' to exit ]";
         sem_wait(&semaphore);
         sem_destroy(&semaphore);
     } catch (...) {
-        // pass
+        sem_destroy(&semaphore);
+        LOG(sls::logINFOBLUE) << "Exiting [ Tid: " << gettid() << " ]";
+        throw;
     }
     LOG(sls::logINFOBLUE) << "Exiting [ Tid: " << gettid() << " ]";
     LOG(sls::logINFO) << "Exiting Receiver";
-    return 0;
+    return EXIT_SUCCESS;
 }
diff --git a/slsReceiverSoftware/tests/CMakeLists.txt b/slsReceiverSoftware/tests/CMakeLists.txt
index 9a9455408..aed52be0c 100755
--- a/slsReceiverSoftware/tests/CMakeLists.txt
+++ b/slsReceiverSoftware/tests/CMakeLists.txt
@@ -4,6 +4,7 @@ target_sources(tests PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/test-GeneralData.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/test-CircularFifo.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/test-ArrangeDataBasedOnBitList.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/test-Apps.cpp
 )
 
 target_include_directories(tests PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../src>")
diff --git a/slsReceiverSoftware/tests/test-Apps.cpp b/slsReceiverSoftware/tests/test-Apps.cpp
new file mode 100644
index 000000000..f7921a6af
--- /dev/null
+++ b/slsReceiverSoftware/tests/test-Apps.cpp
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+#include "CommandLineOptions.h"
+#include "catch.hpp"
+#include "sls/versionAPI.h"
+
+#include <unistd.h>
+
+namespace sls {
+
+template <typename T, typename U> constexpr bool is_type() {
+    return std::is_same_v<std::decay_t<U>, T>;
+}
+
+TEST_CASE("CommandLineOption construction", "[.rxcmdcall]") {
+    CommandLineOptions s(AppType::SingleReceiver);
+    REQUIRE(s.getTypeString() == "slsReceiver");
+    REQUIRE(s.getVersion() ==
+            std::string("slsReceiver Version: ") + APIRECEIVER);
+    REQUIRE_NOTHROW(s.getHelpMessage());
+
+    CommandLineOptions m(AppType::MultiReceiver);
+    REQUIRE(m.getTypeString() == "slsMultiReceiver");
+    REQUIRE(m.getVersion() ==
+            std::string("slsMultiReceiver Version: ") + APIRECEIVER);
+    REQUIRE_NOTHROW(m.getHelpMessage());
+
+    CommandLineOptions f(AppType::FrameSynchronizer);
+    REQUIRE(f.getTypeString() == "slsFrameSynchronizer");
+    REQUIRE(f.getVersion() ==
+            std::string("slsFrameSynchronizer Version: ") + APIRECEIVER);
+    REQUIRE_NOTHROW(f.getHelpMessage());
+}
+
+TEST_CASE("Validate common options", "[.rxcmdcall]") {
+    std::string uidStr = std::to_string(getuid());
+
+    for (auto app : {AppType::SingleReceiver, AppType::MultiReceiver,
+                     AppType::FrameSynchronizer}) {
+        CommandLineOptions s(app);
+        REQUIRE_NOTHROW(s.parse({}));
+        REQUIRE_NOTHROW(s.parse({"", "-v"}));
+        REQUIRE_NOTHROW(s.parse({"", "-h"}));
+        REQUIRE_NOTHROW(s.parse({"", "-h", "gdfg"})); // ignored extra args
+        REQUIRE_NOTHROW(s.parse({"", "-p", "1955"}));
+        REQUIRE_NOTHROW(s.parse({"", "-u", uidStr}));
+        REQUIRE_NOTHROW(s.parse({"", "-p", "1234", "-u", uidStr}));
+    }
+}
+
+TEST_CASE("Validate specific options", "[.rxcmdcall]") {
+    std::string uidStr = std::to_string(getuid());
+
+    CommandLineOptions s(AppType::SingleReceiver);
+    REQUIRE_NOTHROW(s.parse({"", "-t", "1955"}));
+    REQUIRE_THROWS(s.parse({"", "-c"}));
+    REQUIRE_THROWS(s.parse({"", "-n", "2"}));
+    REQUIRE_THROWS(s.parse({"", "-m", "2"}));
+
+    for (auto app : {AppType::MultiReceiver, AppType::FrameSynchronizer}) {
+        CommandLineOptions m(app);
+        REQUIRE_NOTHROW(m.parse({"", "-c"}));
+        REQUIRE_NOTHROW(m.parse({"", "-n", "2"}));
+        REQUIRE_NOTHROW(
+            m.parse({"", "-p", "1234", "-u", uidStr, "-c", "-n", "2"}));
+        REQUIRE_THROWS(m.parse({"", "-t", "1955"}));
+        REQUIRE_THROWS(m.parse({"", "-m", "2"}));
+    }
+}
+
+TEST_CASE("Parse version and help", "[.rxcmdcall]") {
+    for (auto app : {AppType::SingleReceiver, AppType::MultiReceiver,
+                     AppType::FrameSynchronizer}) {
+        CommandLineOptions s(app);
+        auto opts = s.parse({});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.versionRequested == false); // default
+                REQUIRE(o.helpRequested == false);    // default
+            },
+            opts);
+
+        opts = s.parse({"", "-v"});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.versionRequested == true);
+                REQUIRE(o.helpRequested == false);
+            },
+            opts);
+
+        opts = s.parse({"", "-h"});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.versionRequested == false);
+                REQUIRE(o.helpRequested == true);
+            },
+            opts);
+
+        opts = s.parse({"", "-h", "-v"});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.versionRequested == false); // exits after help
+                REQUIRE(o.helpRequested == true);
+            },
+            opts);
+
+        opts = s.parse({"", "-v", "-h"});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.helpRequested == false); // exits after version
+                REQUIRE(o.versionRequested == true);
+            },
+            opts);
+
+        opts = s.parse({"", "-v", "-h", "sdfsf"}); // ignores extra args
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.helpRequested == false); // exits after version
+                REQUIRE(o.versionRequested == true);
+            },
+            opts);
+    }
+}
+
+TEST_CASE("Parse port and uid", "[.rxcmdcall]") {
+    uid_t uid = getuid();
+    std::string uidStr = std::to_string(uid);
+    uid_t invalidUid = uid + 1000;
+    std::string invalidUidStr = std::to_string(invalidUid);
+
+    for (auto app : {AppType::SingleReceiver, AppType::MultiReceiver,
+                     AppType::FrameSynchronizer}) {
+        CommandLineOptions s(app);
+        REQUIRE_THROWS(
+            s.parse({"", "-p", "1234", "-u", invalidUidStr})); // invalid uid
+        REQUIRE_THROWS(s.parse({"", "-p", "500"}));            // invalid port
+
+        auto opts = s.parse({"", "-p", "1234", "-u", uidStr});
+        std::visit(
+            [&](const auto &o) {
+                REQUIRE(o.port == 1234);
+                REQUIRE(o.userid == uid);
+            },
+            opts);
+
+        opts = s.parse({"", "-p", "5678"});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.port == 5678);
+                REQUIRE(o.userid == static_cast<uid_t>(-1)); // default
+            },
+            opts);
+
+        opts = s.parse({});
+        std::visit(
+            [](const auto &o) {
+                REQUIRE(o.port == 1954);                     // default
+                REQUIRE(o.userid == static_cast<uid_t>(-1)); // default
+            },
+            opts);
+    }
+}
+
+TEST_CASE("Parse num receivers and opt arg (Specific opt)", "[.rxcmdcall]") {
+    for (auto app : {AppType::MultiReceiver, AppType::FrameSynchronizer}) {
+        CommandLineOptions s(app);
+
+        REQUIRE_THROWS(s.parse({"", "-n", "0"})); // invalid number of receivers
+        REQUIRE_THROWS(s.parse({"", "-n", "1001"})); // exceeds max receivers
+        REQUIRE_NOTHROW(s.parse({"", "-n", "10"}));  // valid
+
+        auto opts = s.parse({""});
+        std::visit(
+            [](const auto &o) {
+                using T = decltype(o);
+                if constexpr (is_type<MultiReceiverOptions, T>()) {
+                    REQUIRE(o.numReceivers == 1); // default
+                    REQUIRE(o.callbackEnabled == false);
+
+                } else if constexpr (is_type<FrameSyncOptions, T>()) {
+                    REQUIRE(o.numReceivers == 1); // default
+                    REQUIRE(o.printHeaders == false);
+                }
+            },
+            opts);
+
+        opts = s.parse({"", "-n", "5"});
+        std::visit(
+            [](const auto &o) {
+                using T = decltype(o);
+                if constexpr (is_type<MultiReceiverOptions, T>()) {
+                    REQUIRE(o.numReceivers == 5);
+                    REQUIRE(o.callbackEnabled == false); // default
+
+                } else if constexpr (is_type<FrameSyncOptions, T>()) {
+                    REQUIRE(o.numReceivers == 5);
+                    REQUIRE(o.printHeaders == false); // default
+                }
+            },
+            opts);
+
+        opts = s.parse({"", "-c", "-n", "3"});
+        std::visit(
+            [](const auto &o) {
+                using T = decltype(o);
+                if constexpr (is_type<MultiReceiverOptions, T>()) {
+                    REQUIRE(o.numReceivers == 3);
+                    REQUIRE(o.callbackEnabled == true);
+
+                } else if constexpr (is_type<FrameSyncOptions, T>()) {
+                    REQUIRE(o.numReceivers == 3);
+                    REQUIRE(o.printHeaders == true);
+                }
+            },
+            opts);
+    }
+}
+
+TEST_CASE("Parse deprecated options", "[.rxcmdcall]") {
+    for (auto app : {AppType::SingleReceiver, AppType::MultiReceiver,
+                     AppType::FrameSynchronizer}) {
+        CommandLineOptions s(app);
+        // argc 3 or 4, invalid
+        REQUIRE_THROWS(s.parse({"", "1954"}));
+        REQUIRE_THROWS(s.parse({
+            "",
+            "1954",
+        }));
+        // argc 3 or 4
+        if (app == AppType::SingleReceiver) {
+            REQUIRE_THROWS(
+                s.parse({"", "1954", "1"})); // deprecated unsupported
+        } else {
+            REQUIRE_THROWS(s.parse({"", "1954", "1", "1", "-p",
+                                    "1954"})); // mix deprecated and current
+            REQUIRE_THROWS(
+                s.parse({"", "1954", "1", "-c"})); // mix deprecated and current
+            REQUIRE_THROWS(s.parse(
+                {"", "1954", "1", "-n", "34"})); // mix deprecated and current
+            REQUIRE_THROWS(s.parse({"", "110", "1954"})); // mix order
+            REQUIRE_THROWS(s.parse({"", "1023", "10"}));  // privileged port
+            REQUIRE_THROWS(s.parse({"", "2000", "0"})); // invalid num receivers
+            REQUIRE_THROWS(
+                s.parse({"", "2000", "1001"})); // invalid num receivers
+            REQUIRE_THROWS(s.parse({"", "1954", "1", "2"})); // invalid 3rd opt
+
+            REQUIRE_NOTHROW(s.parse({""}));
+            REQUIRE_NOTHROW(s.parse({"", "1954", "1"}));
+            REQUIRE_NOTHROW(s.parse({"", "1954", "1", "0"}));
+            REQUIRE_NOTHROW(s.parse({"", "1954", "1", "1"}));
+
+            // default
+            auto opts = s.parse({""});
+            std::visit(
+                [](const auto &o) {
+                    using T = decltype(o);
+                    if constexpr (is_type<MultiReceiverOptions, T>()) {
+                        REQUIRE(o.port == 1954);
+                        REQUIRE(o.numReceivers == 1);
+                        REQUIRE(o.callbackEnabled == false);
+
+                    } else if constexpr (is_type<FrameSyncOptions, T>()) {
+                        REQUIRE(o.port == 1954);
+                        REQUIRE(o.numReceivers == 1);
+                        REQUIRE(o.printHeaders == false); // default
+                    }
+                },
+                opts);
+
+            opts = s.parse({"", "1958", "10"});
+            std::visit(
+                [](const auto &o) {
+                    using T = decltype(o);
+                    if constexpr (is_type<MultiReceiverOptions, T>()) {
+                        REQUIRE(o.port == 1958);
+                        REQUIRE(o.numReceivers == 10);
+                        REQUIRE(o.callbackEnabled == false); // default
+
+                    } else if constexpr (is_type<FrameSyncOptions, T>()) {
+                        REQUIRE(o.port == 1958);
+                        REQUIRE(o.numReceivers == 10);
+                        REQUIRE(o.printHeaders == false); // default
+                    }
+                },
+                opts);
+
+            opts = s.parse({"", "1958", "10", "1"});
+            std::visit(
+                [](const auto &o) {
+                    using T = decltype(o);
+                    if constexpr (is_type<MultiReceiverOptions, T>()) {
+                        REQUIRE(o.port == 1958);
+                        REQUIRE(o.numReceivers == 10);
+                        REQUIRE(o.callbackEnabled == true); // default
+
+                    } else if constexpr (is_type<FrameSyncOptions, T>()) {
+                        REQUIRE(o.port == 1958);
+                        REQUIRE(o.numReceivers == 10);
+                        REQUIRE(o.printHeaders == true); // default
+                    }
+                },
+                opts);
+        }
+    }
+
+    // test function directly
+    // nargs can be 1, 3 or 4
+    REQUIRE_THROWS(CommandLineOptions::ParseDeprecated({"", ""}));
+    REQUIRE_THROWS(CommandLineOptions::ParseDeprecated({"", "", "", "", ""}));
+
+    // default
+    auto [p, n, o] = CommandLineOptions::ParseDeprecated({""});
+    REQUIRE(p == 1954);
+    REQUIRE(n == 1);
+    REQUIRE(o == false);
+
+    std::tie(p, n, o) = CommandLineOptions::ParseDeprecated({"", "1955", "6"});
+    REQUIRE(p == 1955);
+    REQUIRE(n == 6);
+    REQUIRE(o == false);
+
+    std::tie(p, n, o) =
+        CommandLineOptions::ParseDeprecated({"", "1955", "6", "1"});
+    REQUIRE(p == 1955);
+    REQUIRE(n == 6);
+    REQUIRE(o == true);
+}
+} // namespace sls
\ No newline at end of file
diff --git a/slsSupportLib/include/sls/network_utils.h b/slsSupportLib/include/sls/network_utils.h
index cce2c429d..ac5074abf 100644
--- a/slsSupportLib/include/sls/network_utils.h
+++ b/slsSupportLib/include/sls/network_utils.h
@@ -90,4 +90,5 @@ MacAddr InterfaceNameToMac(const std::string &inf);
 IpAddr InterfaceNameToIp(const std::string &ifn);
 void validatePortNumber(uint16_t port);
 void validatePortRange(uint16_t startPort, int numPorts);
+void setupSignalHandler(int signal, void (*handler)(int));
 } // namespace sls
diff --git a/slsSupportLib/src/network_utils.cpp b/slsSupportLib/src/network_utils.cpp
index 423e9825a..28072259b 100644
--- a/slsSupportLib/src/network_utils.cpp
+++ b/slsSupportLib/src/network_utils.cpp
@@ -1,11 +1,12 @@
 // SPDX-License-Identifier: LGPL-3.0-or-other
 // Copyright (C) 2021 Contributors to the SLS Detector Package
+#include "sls/network_utils.h"
 #include "sls/sls_detector_exceptions.h"
 
-#include "sls/network_utils.h"
 #include <algorithm>
 #include <arpa/inet.h>
 #include <cassert>
+#include <csignal>
 #include <cstdlib>
 #include <cstring>
 #include <ifaddrs.h>
@@ -205,17 +206,27 @@ MacAddr InterfaceNameToMac(const std::string &inf) {
 }
 
 void validatePortNumber(uint16_t port) {
-    // random local port. might work if internal = bad practise
-    if (port == 0) {
-        throw RuntimeError("Invalid port number. Must be between 1 - 65535.");
+    if (port < 1024 || port > std::numeric_limits<uint16_t>::max()) {
+        throw RuntimeError(std::string("Invalid port number ") +
+                           std::to_string(port) +
+                           ". Must be between 1024 - 65535.");
     }
 }
 
 void validatePortRange(uint16_t startPort, int numPorts) {
     validatePortNumber(startPort);
-    if ((startPort + numPorts) > std::numeric_limits<uint16_t>::max()) {
-        throw RuntimeError("Invalid port range. Must be between 1 - 65535.");
-    }
+    validatePortNumber(startPort + numPorts - 1);
 }
 
+void setupSignalHandler(int signal, void (*handler)(int)) {
+    // Catch signal SIGINT to close files and call destructors properly
+    struct sigaction sa {};
+    sa.sa_handler = handler;
+    sigemptyset(&sa.sa_mask); // dont block additional signals
+    sa.sa_flags = 0;
+    if (sigaction(signal, &sa, nullptr) == -1) {
+        throw RuntimeError("Could not set handler for " +
+                           std::string(strsignal(signal)));
+    }
+}
 } // namespace sls