The document provides an introduction to Linux basics. It discusses that Linux is an open-source, Unix-like operating system used widely for servers, desktops, and other devices. It then outlines some common Linux distributions, components of the Linux system like bash and users/groups, and tools for monitoring and managing processes like ps and top.

1. Linux Basics Part 1 OSU Picture © Greg Keene

2. Introductions Lance Albertson Greg Lund-Chaix source: http://shesawake.com/

3. Goals for this Talk Linux Overview

4. Linux distributions

5. System overview

6. More detail: permissions, processes, package management, services

7. Linux Overview Unix-like operating system

8. Free, open source software

9. Runs servers, desktops, phones, tablets, network equipment and more.

10. Linux Statistics Supercomputers More than 90% of the top 500

11. Number of distributions More than 350

12. Number of developers 1,000 developers contributed in 2010

13. Number of commits to linux kernel last year 195,579 commits in 2010

14. Linux Distributions Packaging of applications around a Linux kernel

15. Different distributions have different target audiences

16. Distribution lifecycles vary source: http://www.guilfordlug.org

17. Common Linux Distributions Fedora / RedHat Enterprise / CentOS

18. Debian / Ubuntu / Mint

19. Gentoo / Arch source: http://www.guilfordlug.org

20. Choosing a Distribution Server/desktop/other

21. Existing infrastructure

22. Admin experience

23. Support contract

24. Release supported lifetime

25. Linux System Overview source: wikipedia

26. bash: Bourne Again SHell Default shell on Linux

27. Originally based off of the Bourne Shell (sh)

28. Learn it, live it, love it

29. Basic bash commands ls *.txt file1.txt file2.txt file3.txt ls *.txt > list for i in `cat list`; do cp "$i" "$i".bak ; done ls *.txt* file2.txt file1.txt.bak file2.txt file2.txt.bak file3.txt file3.txt.bak

30. Documentation Most packages include man pages for documentation

31. More extensive than the --help flag on CLI

32. Stored in different 'sections' Picture © Flickr user 'bobeirasa'

33. Users and Groups Users and groups are stored in /etc/passwd and /etc/group

34. Each user name and group name is linked to a number (UID/GID)

35. UID 0 = root

36. 0-99 typically used for system/service accounts

37. File Permissions Three roles: user (file owner), group, other (“world”)

38. Three permissions: read, write, execute Picture © Flickr user 'amagil'

39. root user root user = full access to everything on the system sudo , su – change user Don't use root user unless you have to! Comic: http://xkcd.com/149/

40. Components of a process PID: Process ID number

41. PPID: Parent PID

42. UID & EUID: real & effective user ID

43. GID & EGID: real & effective group ID

44. Niceness

45. Control terminal

46. Signals Sent to procs as communication

47. Sent to terminal driver to kill, interrupt, or suspend

48. Sent by admin to kill

49. Sent by kernel Picture © Flickr user 'atomicshark'

50. Signals: Types you should know HUP, INT, QUIT, KILL, BUS, SIGV, TERM, STOP, TSTP, CONT, WINCH, USR1, USR2 Can catch, block, or dump core? BUS & SEGV – error signals

51. KILL & STOP – cannot be blocked

52. WINCH – term emulators

53. ps: monitor processes primary tool for monitoring processes

54. differ between UNIX's

55. show PID, UID, priority, control term, memory, status, etc

56. complex over the years, archaic

57. pstree

58. top: monitor in real-time “ big picture” in real time

59. refreshes every 2-3 seconds

60. kill, renice, sort, memory, etc.

61. htop – even better color, prettier, more configurable Picture © United Artists from 'Hackers'