diff --git a/src/commands/__init__.py b/src/commands/__init__.py
new file mode 100644
index 0000000..a447c40
--- /dev/null
+++ b/src/commands/__init__.py
@@ -0,0 +1,325 @@
+import inspect
+from threading import Thread
+from unicodedata import numeric
+
+def is_number(s):
+    try:
+        float(s)
+        return True
+    except ValueError:
+        pass
+    return False
+
+class Commands(Thread):
+    defmod = None
+
+    def __init__(self, config, log):
+        super().__init__()
+        self.threaded = False
+        self.cmods = {}
+        self.config = config
+        self.log = log
+        self.stopped = False
+        self.nickname = None
+        if not (self.config is None):
+            self.nickname = self.config.get('nickname')
+
+    def val_to_print(self, val, dig=1):
+        if isinstance(val, str):
+            return val
+        if isinstance(val, float):
+            f = '{:.' + str(int(dig)) + 'f}'
+            return f.format(val)
+        else:
+            return str(val)
+
+
+    def info(self, msg):
+        if self.log:
+            self.log.info(msg)
+        else:
+            print('info:    '+msg)
+
+    def debug(self, msg):
+        if self.log:
+            self.log.debug(msg)
+        else:
+            print('debug:   '+msg)
+
+    def warning(self, msg):
+        if self.log:
+            self.log.warning(msg)
+        else:
+            print('warning: '+msg)import inspect
+from threading import Thread
+from unicodedata import numeric
+
+def is_number(s):
+    try:
+        float(s)
+        return True
+    except ValueError:
+        pass
+    return False
+
+class Commands(Thread):
+    defmod = None
+
+    def __init__(self, config, log):
+        super().__init__()
+        self.threaded = False
+        self.cmods = {}
+        self.config = config
+        self.log = log
+        self.stopped = False
+        self.nickname = None
+        if not (self.config is None):
+            self.nickname = self.config.get('nickname')
+
+    def val_to_print(self, val, dig=1):
+        if isinstance(val, str):
+            return val
+        if isinstance(val, float):
+            f = '{:.' + str(int(dig)) + 'f}'
+            return f.format(val)
+        else:
+            return str(val)
+
+
+    def info(self, msg):
+        if self.log:
+            self.log.info(msg)
+        else:
+            print('info:    '+msg)
+
+    def debug(self, msg):
+        if self.log:
+            self.log.debug(msg)
+        else:
+            print('debug:   '+msg)
+
+    def warning(self, msg):
+        if self.log:
+            self.log.warning(msg)
+        else:
+            print('warning: '+msg)
+
+    def error(self, msg):
+        if self.log:
+            self.log.error(msg)
+        else:
+            print('error:   '+msg)
+
+    def stop(self):
+        self.stopped = True
+
+    def list_modules(self):
+        success = True
+        ret = ''
+        for module in self.cmods.keys():
+            ret = ret + module + '\n'
+        return success, ret.strip()
+
+    def _execute_command(self, cmd):
+        c = cmd.split(',', maxsplit=1)
+        key = "cmd_" + c[0].strip().lower().replace(' ', '_')
+        params = []
+
+        #parameters
+        if len(c) > 1:
+            for p in c[1].split(','):
+                p = p.strip()
+                if is_number(p):
+                    params.append(float(p))
+                else:
+                    params.append(p)
+            params = tuple(params)
+
+        success = False
+        ret = "function not found"
+        if hasattr(self, key) and inspect.ismethod(getattr(self, key)):
+            self.lock.acquire()
+            try:
+                f = getattr(self, key)
+                ret = f(*params)
+                success = True
+                self.log.info('function "{}" of module "{}" was called'.format(key, self.name))
+            except TypeError:
+                self.log.error('function "{}" of module "{}" wrong parameters'.format(key, self.name))
+                ret = 'param error'
+            except:
+                self.log.error('function "{}" of module "{}" crashed'.format(key, self.name))
+                ret = 'function crash'
+            self.lock.release()
+
+        if ret is None:
+            ret = ''
+        return success, ret.strip()
+
+    def execute_command(self, cmd):
+        # isolate the module called
+        success = False
+        c = cmd.split('.', maxsplit=1)
+        if ((len(c) == 1) and (self.defmod is None)) or (len(c) < 1):
+            ret = 'Wrong call syntax. It should be: "<module>.<function>=param,param2..."'
+
+            self.log.error(ret)
+            return success, ret
+
+        if (len(c) == 1) and (c[0].lower() == 'help'):
+            return self.list_modules()
+
+        elif len(c) == 1:
+            module = self.defmod
+            command = c[0]
+        else:
+            module = c[0].lower()
+            command = c[1]
+
+        if not (module in self.cmods.keys()):
+            m = module.replace('_','-')
+            if not (m in self.cmods.keys()):
+                ret = 'module "{}" not found'.format(module)
+                self.log.error(ret)
+                return success, ret
+
+        return self.cmods[module]._execute_command(command)
+
+    def cmd_help(self,*args):
+        '''Help of module commands.
+        Params:
+            - if No param:  list of commands
+            - otherwise:    help of the first arg'''
+
+        ret = ''
+
+        if len(args) == 0:
+            cmds = inspect.getmembers(self, predicate=inspect.ismethod)
+            cmds = [x for x in cmds if x[0].startswith('cmd_')]
+            for m in cmds:
+                ret = ret + m[0][len('cmd_'):] + '\n'
+        else:
+            if isinstance(args[0], str):
+                cmd = 'cmd_'+args[0]
+                c = getattr(self, cmd, None)
+                if c:
+                    r = inspect.getdoc(c)
+                    if r:
+                        ret = r
+                    else:
+                        ret = 'No documentation for "' + args[0] + '"'
+
+        if ret == '':
+            ret = 'No command with this name...'
+
+        return ret
+
+    def error(self, msg):
+        if self.log:
+            self.log.error(msg)
+        else:
+            print('error:   '+msg)
+
+    def stop(self):
+        self.stopped = True
+
+    def list_modules(self):
+        success = True
+        ret = ''
+        for module in self.cmods.keys():
+            ret = ret + module + '\n'
+        return success, ret.strip()
+
+    def _execute_command(self, cmd):
+        c = cmd.split(',', maxsplit=1)
+        key = "cmd_" + c[0].strip().lower().replace(' ', '_')
+        params = []
+
+        #parameters
+        if len(c) > 1:
+            for p in c[1].split(','):
+                p = p.strip()
+                if is_number(p):
+                    params.append(float(p))
+                else:
+                    params.append(p)
+            params = tuple(params)
+
+        success = False
+        ret = "function not found"
+        if hasattr(self, key) and inspect.ismethod(getattr(self, key)):
+            self.lock.acquire()
+            try:
+                f = getattr(self, key)
+                ret = f(*params)
+                success = True
+                self.log.info('function "{}" of module "{}" was called'.format(key, self.name))
+            except TypeError:
+                self.log.error('function "{}" of module "{}" wrong parameters'.format(key, self.name))
+                ret = 'param error'
+            except:
+                self.log.error('function "{}" of module "{}" crashed'.format(key, self.name))
+                ret = 'function crash'
+            self.lock.release()
+
+        if ret is None:
+            ret = ''
+        return success, ret.strip()
+
+    def execute_command(self, cmd):
+        # isolate the module called
+        success = False
+        c = cmd.split('.', maxsplit=1)
+        if ((len(c) == 1) and (self.defmod is None)) or (len(c) < 1):
+            ret = 'Wrong call syntax. It should be: "<module>.<function>=param,param2..."'
+
+            self.log.error(ret)
+            return success, ret
+
+        if (len(c) == 1) and (c[0].lower() == 'help'):
+            return self.list_modules()
+
+        elif len(c) == 1:
+            module = self.defmod
+            command = c[0]
+        else:
+            module = c[0].lower()
+            command = c[1]
+
+        if not (module in self.cmods.keys()):
+            m = module.replace('_','-')
+            if not (m in self.cmods.keys()):
+                ret = 'module "{}" not found'.format(module)
+                self.log.error(ret)
+                return success, ret
+
+        return self.cmods[module]._execute_command(command)
+
+    def cmd_help(self,*args):
+        '''Help of module commands.
+        Params:
+            - if No param:  list of commands
+            - otherwise:    help of the first arg'''
+
+        ret = ''
+
+        if len(args) == 0:
+            cmds = inspect.getmembers(self, predicate=inspect.ismethod)
+            cmds = [x for x in cmds if x[0].startswith('cmd_')]
+            for m in cmds:
+                ret = ret + m[0][len('cmd_'):] + '\n'
+        else:
+            if isinstance(args[0], str):
+                cmd = 'cmd_'+args[0]
+                c = getattr(self, cmd, None)
+                if c:
+                    r = inspect.getdoc(c)
+                    if r:
+                        ret = r
+                    else:
+                        ret = 'No documentation for "' + args[0] + '"'
+
+        if ret == '':
+            ret = 'No command with this name...'
+
+        return ret
\ No newline at end of file
diff --git a/src/main.py b/src/main.py
new file mode 100644
index 0000000..f844322
--- /dev/null
+++ b/src/main.py
@@ -0,0 +1,132 @@
+#!/usr/bin/python3
+
+import os
+import configparser
+import logging
+from systemd import journal
+import inspect
+from importlib import import_module
+from commands import Commands
+from threading import Lock
+
+ourpath = os.path.dirname(os.path.abspath(__file__))
+
+
+def dir_writeable(path):
+    return os.access(path, os.W_OK)
+
+
+class CommandsLoader:
+    def __init__(self, config, log):
+        self.config = config
+        Commands.defmod = self.config['general'].get('default')
+        self.log = log
+        self.lock = Lock()
+        self._load_commands()
+        self._set_cmods()
+        self._load_dependencies()
+
+    def _load_commands(self):
+        cmds = {}
+        with os.scandir(os.path.join(ourpath, "commands")) as it:
+            for entry in it:
+                if entry.name.startswith('cmds_') and entry.name.endswith('.py') and entry.is_file():
+                    obj = self._load_module(entry.name[:-3])
+                    if not obj is None:
+                        nmod = obj.nickname
+                        if nmod is None:
+                            nmod = (entry.name[:-3])[5:]
+                        cmds.update({nmod: obj})
+                        self.log.info('module "{}" loaded'.format(nmod))
+                    else:
+                        self.log.error(
+                            'The module "{}" could not be loaded'.format(entry.name[:-3]))
+        self.cmods = cmds
+
+    def _load_module(self, name):
+        module = import_module("."+name, 'commands')
+        members = inspect.getmembers(module, inspect.isclass)
+        conf = None
+        if name[5:] in self.config.sections():
+            conf = self.config[name[5:]]
+
+        obj = None
+        for n, c in members:
+            if issubclass(c, Commands) and (n != 'Commands'):
+                obj = c(conf, self.log)
+                obj.log = self.log
+                obj.lock = self.lock
+                break
+
+        return obj
+
+    def _set_cmods(self):
+        for k, v in self.cmods.items():
+            v.cmods = self.cmods
+
+    def _load_dependencies(self):
+        for k, v in self.cmods.items():
+            if hasattr(v, "dependencies"):
+                for p in v.dependencies:
+                    if p in self.cmods.keys():
+                        setattr(v, p, self.cmods[p])
+                    else:
+                        log.error(
+                            'Dependency "{}" of module "{}" could not be satisfied'.format(p, k))
+
+    def start(self):
+        for k, v in self.cmods.items():
+            if v.threaded:
+                v.start()
+
+    def join(self):
+        for k, v in self.cmods.items():
+            if v.threaded:
+                v.join()
+
+
+if __name__ == "__main__":
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-c", "--config", help="Configuration file", default='/etc/sms-server.conf')
+    parser.add_argument("-l", "--log-file", help="log to a file instead of the console",
+                        default='')
+    parser.add_argument("-g", "--debug", action='store_true', required=False,
+                        help="Debug messages logged")
+    args = parser.parse_args()
+
+    if os.path.exists(args.config):
+        conf = configparser.ConfigParser()
+        conf.read(args.config)
+    else:
+        raise Exception('Configuration file not found')
+
+    log = logging.getLogger(os.path.basename(__name__))
+    if args.log_file != '':
+        fname = args.log_file
+        is_writeable = False
+
+        if not os.path.isabs(fname):
+            fname = os.path.join(os.getcwd(), fname)
+
+        if dir_writeable(os.path.dirname(fname)):
+            is_writeable = True
+
+        if is_writeable:
+            log.addHandler(logging.FileHandler(fname))
+        else:
+            log.addHandler(journal.JournalHandler())
+            log.error('No write permissions: "{}"'.format(fname))
+
+    else:
+        log.addHandler(journal.JournalHandler())
+
+    if args.debug:
+        log.setLevel(logging.DEBUG)
+    else:
+        log.setLevel(logging.WARNING)
+
+    cl = CommandsLoader(conf, log)
+    cl.start()
+    cl.join()