How to learn

learn by practise, ask yourself a few questions
also can be used in other fields

The only way to see if you really understand something is to try it yourself.

1 What does that do?

2 How does that work?

Learning about Unix from Unix

just like search in a dictionary or on the internet

  • Read the manual
  • Search the manual
  • Read the .h files
  • follow SEE ALSO links

3 Can I try to do it?

  • write
  • compare to the original
  • learn more and update

4 How can I make this run better?

System calls consume time.
Minimize the number of system calls, e.g., suitable buffer size.

System Calls


  • open
  • creat
  • read
  • write
  • lseek
  • close


  • perror