diff --git a/README.md b/README.md
index ce39975..85ca07a 100644
--- a/README.md
+++ b/README.md
@@ -11,16 +11,18 @@ At the moment, an alpha version is undertaken, with these features:
 - The sqlite-database holds a growing number of piano-solo pieces, together with their exact catalogue-numbers and composers.
 - Prepared in this database is a table for users (pianists), that marks which of the pieces can be played.
 
-### Application
+### Application and usage
 
-- Create new users
-- Set an active user
-- Show the pieces stored in the database
-- (planned) Mark pieces as masterd for the active user
+- Create new users (`n username`)
+- Show users (`su`)
+- Set an active user (`a number_of_user`)
+- Show the pieces stored in the database (`s`)
+- Mark pieces as mastered for the active user (`m number_of_work`)
 - (planned) Show pieces by composer
-- (planned) Show movements throug pieces
+- (planned) Show movements through pieces
 
 ## Requirements
 
 - Python 3.9 or higher
-- Enough disk space to hold the database
\ No newline at end of file
+- Enough disk space to hold the database
+- run `python builddb.py` to build the SQLite-database-file before running `python rep_cli.py`
\ No newline at end of file
diff --git a/rep_cli.py b/rep_cli.py
index fc71581..aaa9029 100644
--- a/rep_cli.py
+++ b/rep_cli.py
@@ -29,6 +29,8 @@ class Session:
         self.resultstring = ''
         if command == 'a':
             self.resultstring += self.set_user(arguments[0])
+        elif command == 'm':
+            self.resultstring += self.mark_work_as_mastered(arguments[0])
         elif command == 'n':
             self.create_new_user(arguments[0], arguments[1])
             self.resultstring += f'Created new user {arguments[0]} {arguments[1]}.'
@@ -76,6 +78,17 @@ class Session:
             fun_resultstring += f'{work.id()}: {work.pretty_string()}\n'
         return fun_resultstring
 
+    def mark_work_as_mastered(self, work_id):
+        resultstring = 'adding:\n'
+        work = work_under_id(work_id, self.db_agent)
+        for mov_number in work.values['movements'].keys():
+            sql_command = f'''
+                          INSERT INTO is_able_to_play (work_id, mov_id, pianist_id)
+                          VALUES ({work_id}, {mov_number}, {self.user})
+                          '''
+            self.db_agent.execute(sql_command)
+            resultstring += f'{work.pretty_mov(mov_number)}\n'
+        return resultstring
 
 # End session
 
@@ -149,6 +162,35 @@ class work_under_id:
                     ret_str += f'{self.values[key]} '
         return ret_str
 
+    def pretty_mov(self, mov_number):
+        ret_str = ''
+        for key in ['first_name', 'name',
+                    'title', 'mov_title', 'opus', 'numb',
+                    'main_key', 'alias',
+                    'movements',
+                    'work_directory','wd_number']:
+            if key in self.values.keys() and not self.values[key] is None:
+                if key == 'opus':
+                    ret_str += f'op. {self.values[key]} '
+                elif key == 'name':
+                    ret_str += f'{self.values[key]}, '
+                elif key == 'numb':
+                    ret_str += f'Nr. {self.values[key]} '
+                elif key == 'movements':
+                    if self.values[key][mov_number][1] is None:
+                        ret_str += ''
+                    else:
+                        if len(self.values[key]) > 1:
+                            ret_str += f'{mov_number}. {self.values[key][mov_number][1]} '
+                        else:
+                            ret_str += f'{self.values[key][mov_number][1]} '
+                elif key == 'title':
+                    if self.values['mov_title'] is None:
+                        ret_str += f'{self.values[key]} '
+                else:
+                    ret_str += f'{self.values[key]} '
+        return ret_str
+
     def __str__(self):
         ret_str = ''
         for key, value in self.values.items():
@@ -161,7 +203,7 @@ class work_under_id:
 def parse_user_input(user_in):
     split_user_in = user_in.split()
     command = split_user_in[0]
-    if command in ('a', 'n', 'q', 's', 'su'):
+    if command in ('a', 'm', 'n', 'q', 's', 'su'):
         arguments = split_user_in[1:]
         return (command, arguments)
     else: