text: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  
  # FEATURES: os interface, system info, environment, lightweight process management
  import os
  import signal
  
  print("\n### Basic system information")
  print(f"Operating sistem simple name: \"{os.name}\"")
  #print(f"Operation sysrtem specific name: \"{os.uname()}\"")
  
  
  print("\n### Environment")
  print(f"Environment as string: \"{os.environ}\"")
  #print(f"Environment as bytes: \"{os.environb}\"")
  
  print(f"Get env value for key \"foo\": \"{os.getenv('foo', 'default : foo not defined yet')}\"")
  print(f"Set env value for key \"foo\" to \"bar\" # 1")
  os.putenv('foo', 'bar')
  
  print(f"Get env value for key \"foo\": \"{os.getenv('foo', 'default : foo defined byt environ not updated')}\"")
  print(f"Set env value for key \"foo\" to \"bar\" # 2")
  os.environ['foo'] = 'bar'
  
  print(f"Get env value for key \"foo\": \"{os.getenv('foo', 'default : assigning to os.environmrnt fileds is prefered')}\"")
  
  
  print("\n### Process management")
  print(f"Path where binaries are serched for: \"{os.get_exec_path()}\"")
  #print(f"Current user name: \"{os.getlogin()}\"")
  
  print("Print current diorectory using call to external program")
  if os.name == "posix":
      os.system("ls")
  else:
      os.system("dir")
  
  pid = os.getpid()
  print(f"PID of the current process is {pid}")
  
  print("Kill process using PID, kill this process")
  os.kill(pid, signal.SIGINT)