Linux Overview Marx Jerez mjerez@funmrd.ve Alejandro Gonzalez ale@ula.ve

1. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Linux Overview Marx Jerez mjerez@funmrd.gov.ve Alejandro Gonzalez ale@ula.ve Gilberto Diaz gilberto@ula.ve Los Andes University - Fundacite Mérida - Venezuela

2. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Until now, according to the networking world, we have studied the details of the layer 1 of OSI model (physic layer) One of ours aims is create an infrastructure to exchage information In order to satisfy this, we need some network service, but before we need use a good platform to do it.

3. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 What is Linux? Linux is the core of a operating system, the so called “kernel”. It executes the applications and interacts with the hardware. It was written in 1991 by Linus Torvalds but now include code of thousand of programmers around the world. This kernel is combined with many others applications and tools that all together form the operating system known as Linux o GNU/Linux http://www.lugatgt.org/articles/overview/

4. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 What are Distributions? Currently, there are a lot of applications and programs to do different tasks and they are dedicated to satisfy different purposes: image processing, editors, communications, network services, etc. Companies like Red Hat, Slackware, SUSE, Debian, etc. collect their own set of applications, modify the kernel and build an installation program. This compilation of applications, kernels and installers are called distribution.

5. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 GPL Gnu Public License: This license establish that any software developed under it can be used in any way, modified and copied. But, you can not claim falsely that you wrote the entire application, and any change that you do must be shared with the community. Linux kernel and it application is under GPL.

6. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Who owns and control Linux? There is not a single entity in charge of Linux or owns it. This is by and for hobbyists, hackers, and professionals worldwide. However, Linus does own the name, "Linux"

7. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Why use Linux in wireless networks? • Stable operating system • Best cost – effective solution for: routers, AP, firewall, monitoring station, etc. • Easy remote administration and is not heavy to do it trough the network

8. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Linux Structure Applications Shells Kernel Hardware

9. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 The Kernel • Is the part of the O.S that interacts directly with the hardware. • Its main function is: • Memory management. • Computer access control. • Maintenance the file systems, interrupts management. • Error and IO services management. .

10. End of quantum School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 The Kernel - Time sharing

11. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 The Kernel - Multitasking - Multiuser - Almost completely written in C. - TCP/IP - POSIX.

12. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 The Shell • Is the interface between the user and the O.S. • Command interpreter. • Read instructions and interpret them as programs execution.. • Has its own program language. • Controls how and when the instructions are executed..

13. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 The Shell • sh UNIX standard shell (Bourne shell). • bash GNU Version of the standard shell. • csh California shell. • jsh Job shell (sh extension) • ksh Korn shell. • tcsh Improved version of csh.

14. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Applicatins and Services - Telnet, ssh - Firewalls - FTP - Router - NIS - DHCP - NFS - Print server - DNS - Communication server - WEB - O.S server - Data Bases - E-mail server - etc.

15. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Installation, Booting and Stopping Linux

16. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Slackware 9.1 Installation First prompt: some special parameters • Keyboards selection • Login as root • Disk partitions (fdisk) • Setup menu • Source installation selection • Target installation selection (what partition) • Packages selection • Format partition (whether or not check) • File system type selection • Inode size

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24. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 • Partition information: • Swap partition (type 82) = at least same RAM size. • Linux native (type 83) = All available space in disk.

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34. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Boot process - Load the kernel - Hardware check. Devices detection and creation - Start system processes. - init process /etc/inittab - File systems check - Mount file systems

35. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Boot process Init Configuration file "inittab" id:3:initdefault: #System initialization si::sysinit:/etc/rc.d/rc.sysinit . . l3:3:wait:/etc/rc.d/rc 3 . .

36. School on Digital Radio Communications for Research and Training in Developing Countries - Febreary 2004 Stopping the system Comando shutdown Reinicio, detención o tareas administrativas de bajo nivel - Envio de señal SIGTERM a los procesos. - Bloqueo de login. - Ejecución del procesos init en nivel 0. desmontaje de sistemas de archivos.

37. School on Digital Radio Communications for Research and Training in Developing Countries Febreary 2004 Linux Basic Commands

38. jose hawee graphics management manual Report graphics1 School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Files management ls rm graphics lpr grafico1 cp graphics graphics/graphics more report cat report tail report mv report management/ wc report

39. School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Files management • Exercise(1): • Run the following commands: • ls • ls -l • ls -a • ls -la • What do you look at in each command? • more report.txt • cat report.txt • less report.txt • tail report.txt

40. School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Files management • Exercise (2): • Run the following commands: • cp report.txt report.txt.old • mv report.txt.old report.txt.orig • ls -a • ls -la • What do you look at in each command? • more report.txt • cat report.txt • less report.txt • tail report.txt tail –l 15 report.txt

41. School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Files management • Exercise (3): • Run the following commands: • gzip report.txt • gunzip report.txt.gz • wc report.txt • diff report.txt report.txt.changed

42. School on Digital Radio Communications for Research and Training in Developing Countries Febreary 2004 Basic Unix Command Directory management home pwd mkdir graphics luis cd graphics cd .. rmdir graphics graphics Search report find / -name .login -print

43. School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Directory management • Exercise(1): • Run the following commands: • cd Return tu your local home • mkdir mydirectory • cd mydirectory • cp ../report.txt ./mydirectory • cd .. • rmdir mydirectory • Does it work? • rm -rf mydirectory

44. School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Directory management • Exercise(1): • Run the following commands: • cd Return tu your local home • mkdir mydirectory • cd mydirectory • cp ../report.txt ./mydirectory • cd .. • rmdir mydirectory • Does it work? • rm -rf mydirectory

45. School on Digital Radio Communications for Research and Training in Developing Countries Febrary 2004 Finding things • grep, egrep, fgrep -- print lines matching a pattern • Example: • grep string filename(s) • find -- search for files in a directory hierarchy • Example • find / -name “report.txt” –print • Locate -- Index and quickly search for files on your system • Example: • locate httpd

46. School on Digital Radio Communications for Research and Training in Developing Countries Febreary 2004 About other people w -- Show who is logged on and what they are doing. who -- show who is logged on finger username -- user information lookup program last -1 username-- show listing of last logged in users talk username -- talk to another user write username -- send a message to another user

47. School on Digital Radio Communications for Research and Training in Developing Countries Febreary 2004 About yourself whoami --- print effective userid finger--- user information lookup program passwd --- update a user's authentication tokens(s) ps -u yourusername --- report process status kill PID --- terminate a process quota -v --- terminate a process du filename --- estimate file space usage last yourusername --- show listing of last logged in users

48. School on Digital Radio Communications for Research and Training in Developing Countries Febreary 2004 Miscellaneous tools cal --- print effective userid date --- print or set the system date and time man --- print or set the system date and time