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  1. Agustin's Linux Manual
  2. System Administration
  3. About the Author
  4. Contents
  5. Administration
  6. Terminals
  7. Command Basics
  8. Root Directory
  9. Executing Commands
  10. File specs
  11. File Permission
  12. How permissions are assigned
  13. Change ownership chown
  14. Running multiple commands
  15. Killing Processes
  16. Bash configuration files
  17. VI Editor
  18. Creating path environment
  19. Midnight Commander
  20. Linuxconf Utility
  21. Networking
  22. Domain Name Service DNS
  23. Router and Gateway
  24. Adding Users
  25. User Accounts
  26. Managing Groups
  27. Mounting File System
  28. NFS Mounts
  29. Disk Quotas
  30. Run levels
  31. Linuxconf Control
  32. Mandrake Control Center
  33. Creating a Boot Disk
  34. Switching Boot Mode
  35. Hardware Configurations
  36. Printer Configuration
  37. Installing Printers
  38. Samba Printer
  39. Managing services
  40. Managing Users
  41. Program Scheduler
  42. Software Management
  43. Installing CUPS

Chapter 3


The most wonderful thing about any operating system is administration. No system is secure and no system is reliable if there is no administration at all. And the worse comes when a wonderful system like Linux is being managed and maintained by a clueless system administrator. The administrator is a hacker, and must know what he/she is working with.

Please do not confuse hackers with crackers or script kiddies.

The best, well-respected hackers are good system administrators who spent their entire lives deploying and protecting systems. These are people who know about real securities such as Network Detection Systems, Network IDS, Finger Printing, etc. Most crackers and script kiddies only know how to destroy systems. Fakers know how to scan for open ports, launch some Distributed Denial of Service (DDOS), and call themselves hackers. What is worse is that the news media confuse them as hackers.

Of course there are exceptions. Sometimes security professionals turn into criminals. Believe me some of them cannot even pay their bills or feed their families because employers rarely value real skills. Employers say, “I am sorry you are over qualified; or, it seems that you are very unstable, you had more than four jobs during the past two years”. Professionals should be respected and paid for what they know or can do.

Oh! Make note that when I say, “professionals”, I am not referring to those who hold a degree or PHD. I am referring to those who struggle every night to offer something to the community and say, “Hey people I discovered last night that the OS Ver. Xx has a security bridge… here's how to fix it”. See, you don't need a degree to say how things are done. Many people forget that a lot of the most skillful professionals did not have enough money to get enrolled in a college or university. And some of those lucky enough to go through certification programs are still waiting for an opportunity for an entry-level position.

Employers look at their resumes and tell them, “I am sorry I can't hire you because you don't have experience”. This person can have control of an entire company's network within three minutes.

Think about it, a computer technician now earns around $7.00 an hour. Why should one work as a computer technician? One can earn $7.00 an hour working at a fast food Restaurant. Most people that are interested in computers don't stop with basic technical skills.

What you see next is for those persons who want to be the best. If you want to be the best, read on. If you want a certificate, print one. It holds just as much value.

Note to employers: Don't ask for a certification from a real I.T. professional. Most real ones don't have one. Instead, test them and pay them for the time they are there.

Welcome to system administration

It is very important that you learn where files are located. You probably will be doing some administration in the near future. If you are a technical person, you have to know your stuff. I am sure you don't want to look clueless when a supervisor asks you, “How I do this”. If he appreciates your work, you will be compensated for your knowledge.

Did you know that you could use Linux without knowing anything about the shell? You can boot your system directly into X and do all kinds of administration from there. You can use the Mandrake Control Center, Webmin and Linuxconf to administer every aspect of your system.

Some people don't like to use console text modes, but others loves it. Believe me you can't say you are a Linux user without knowing how to use the console. Yeah, yeah… the GUI is great and looks nice, etc. Serious users must know how to use the shell.

You must have to know all these amazing things that you can do with the console. In the shell console you can accomplish very highly complex tasks because UNIX isn't just a simple command interpreter; instead it is a highly flexible programming environment.