Linux 103 - Post installation tasks, the Command Line Interface (CLI) and proper package management under Linux by Brian Byrne

Linux 103 - Post installation tasks, the Command Line Interface (CLI) and proper package management under Linux by Brian Byrne

Worshipful Company of Information Technologists,
November 2019

Transcript

1. Linux 103 - Post installation tasks, the Command Line Interface (CLI) and proper package management under Linux by Brian Byrne Worshipful Company of Information Technologists, November 2019 Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 1
2. Brian Byrne is a freelance IT manager, a thinker and do-er for hire. He started coding around 1971, over time he has written programs in 14+ languages, although Turbo Pascal remains one of his favourites. Brian organises Linuxing In London, co-organises Community, Covent Garden Pi Jam and all London Raspberry Pi Jam (mini-science festivals for kids), plus a lot more. He likes tea, good manners and speaking poor Spanish. He prefers community management to being a boring IT Manager and is a bit of a know-all! NB: Brian speaks in paragraphs. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 2
3. What’s an IT Manager? Generally, the ultimate geek! Lives, breathes, smells and loves technology. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 1,400 pages of operating system joy. 3
4. Congratulate yourself! By this stage you have completed either the Linux 101, Linux 103 or Linux 104 You have a working Linux system. Now we have to learn how to manage it. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 4
5. Brief agenda: Post installation, what must be done, what should be done and what could be done. How to operate a Linux system, what to do and what to avoid, covering the Linux command-line extensively. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 5
6. What this class is not: An MSc in computer science. The last word on everything about Linux. But, it will provide: A basic Linux 103, a hands-on approach to managing a Linux system and many of the gotchas! It will be the start of your journey to learnt about Linux. Linux 103 by Brian Byrne. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 6
7. What we will do: Perform post-installation tasks. Optional customisation and nice to have. Learn about command line software installation. The power of the command line interface (CLI), basic commands, key files, performance tuning, etc., Finally, you will be master of your own Linux system. NB: These commands should apply on almost any Debian or Ubuntu derived system: AWS, GCP, etc., but read the manual first. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 7
8. Prerequisites 1. A working Linux system based on Kali Linux, Debian, Ubuntu or similar. 2. Pen and paper. 3. Bags of concentration. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 8
9. Peppermint Linux exercises There will be three special Peppermint Linux exercises to do at the end. 1. Enable bridged networking on the VM instance (Hint: shutdown first) 2. Add a normal user. 3. Install synaptic and then tell us how many packages are available. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 9
10. A word of warning: Linux is not Windows, don’t treat it as if it were. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 10
11. GUI vs CLI what is what? GUI - Graphic User Interface - typically visual and navigated with a mouse or touchpad CLI - Command Line Interface - textual input with a terminal environment Good for the GUI: Synaptic, file management, meld, etc Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 11
12. Commands in Linux on the CLI Verb<space>option option<return> You supply an action word with various parameters then hit the return or enter key. For example, ls -l -h or as ls -hl Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 12
13. Technical demo (switch to Linux laptop) [NB: all Linux commands should be in lowercase, Linux is case sensitive] Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 13
14. 0. Bring up a terminal yourself Menu->[Search bar]Terminal->Click->Terminal Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 14
15. 1. Perform post-installation tasks. Update the software and install more applications. [NB: all Linux commands should be in lowercase, Linux is case sensitive] See point 3. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 15
16. 2. Gotchas, security and what not to do. A word about normal users and root access. Generally, users cannot break a Linux system but root (or superuser) can. sudo <command> sudo -i for a longer session but take extra care. Gotchas: Don’t CTRL-C system updates/upgrades, etc., or you’ll end up with a broken package management system, and your Linux system will, in the end, become broken. Treat Linux with respect or it will bite you back. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 16
17. 3. Perform a complete system upgrade (think Google Store or App Store) sudo -i apt-get update && apt-get -V dist-upgrade [Do it at home by your router, whenever possible. It can take 20-40+ minutes. Watch the output very carefully, for any error ] NB: Take a break, but remember don't interrupt apt-get or it might break your Linux system. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 17
18. 3.1 A word on dependency management and libraries. Only install packages via the build-in package manager, apt-get, dpkg or Synaptic, etc., Do it any other source and you risk busting your package management system and your whole Linux set-up! And if you do it could mean another reinstall from scratch. Be extra careful. [NB: all Linux commands should be in lowercase, Linux is case sensitive] Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 18
19. 4. The order of proper system management on Linux 1. Install the operating system. 2. Reboot. 3. Do an update/upgrade. 4. Reboot. 5. Add any additional accounts. 6. Add any other apps, as required. 7. Check log files and performance. 8. Good to go! Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 19
20. 5. Change defaults and create your own user account 5.1 Type, passwd Pick a new password for the default Linux account. 5.2 sudo -i passwd root [NB: all Linux commands should be in lowercase, Linux is case sensitive] Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 20
21. 5.3 Type, adduser <your new username> [Fill in details, freehand] 5.4 Add to sudo group usermod -aG <your new username> sudo Verify new user account has access to sudo, by logging out and logging in again, then type sudo -i from your new account. If in doubt check /etc/sudoers Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 21
22. 6.2 Finding apps/packages with the command line apt-cache search maths >file more file grep <text to search for> file A typical Linux repository (where packages are kept for later installation) for Peppermint Linux 8 has over 58,000 packages listed. 58,000+. A working system probably has >3000+ packages installed. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 22
23. 6.3 apt-get - is a frontend apt-get is a frontend to dpkg and ALWAYS the best way, but dpkg -l (L) is useful. A partial sample listing is shown below. Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version +++-===========================================================-========================= ii abiword 3.0.1-6ubuntu0.16.04.1 ii abiword-common 3.0.1-6ubuntu0.16.04.1 ii abiword-plugin-grammar 3.0.1-6ubuntu0.16.04.1 ii accountsservice 0.6.40-2ubuntu11.3 ii acl 2.2.52-3 ii acpid 1:2.0.26-1ubuntu2 ii adduser 3.113+nmu3ubuntu4 ... Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com
24. 6. More basics software installation with apt-get 6.1 Installing with the command line apt-get update – are we online? Give me an up to date feel for all of the packages. apt-get –V install <package> E.g. apt-get install –y –V glances Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 24
25. 7. The command line and the shell (bash) There are various shells on Linux (the Bourne shell was created Steven Bourne and default on V7 Unix). Bash - Bourne Again Shell Ksh - Korn shell Fish - friendly interactive shell zsh - extended Bourne shell csh - C shell dash - Debian Almquist shell Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com
26. 7.1 What’s the shell? In UNIX, Linux, BSD (Berkeley Standard distribution) and even OpenVMS (a mainframe operating system), the shell is the program which interprets what you typed on the command line. It then actions it accordingly. That could mean showing you the directory, or bringing up an application, it depends on what you type It offers the flexibility to run scripts (as with Python or similar languages) and it is your main interface to the operating system. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 26
27. 7.2 What am I running? cat /etc/shells echo $SHELL The default in this instance is bash. 7.3 Recall buffer and CTRL-R <CTRL-R> <A letter or 2> Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 27
28. 7.4 The history command Writing the history buffer to a file: history –w whatihavejustdone.txt Clear the history: history –c 7.5 Magical tab command cd Down<tab> Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 28
29. 8. Some basic Linux commands for file management, etc., (think MS-DOS) ls – list files, e.g. ls -alh mkdir – make a directory cd - change to a directory pwd - where am I cd $HOME – take me to the top level directory more – type something to the console mv – really renames files but moves them too (NB: use with care) ... Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 29
30. cp – copy files tail – the bottom of a file, eg. tail <filename> or tail -n 200 <filename> nano – a simple editor rm – erases files, be careful, particularly when in root. rmdir – removed an empty directory diff – compare two files, eg. diff –y –w132 <file1> <file> Linux has a wide range of GUI (graphical user interface) programs too! Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 30
31. 9. Key files and how not to break Linux 9.1 Directories Don’t touch anything in /etc unless you have to. Don’t delete anything from /usr/bin or /usr/sbin/ 9.2 Making space If you need to remove a package use apt-get purge <package> Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 31
32. 9.3 Something broke? Where to look ls –rtcl /var/log is handy tail /var/log/syslog [On systemd? use journalctl] dmesg – watch like a hawk, use -T to make sense of time df -h is useful for overall disk space Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 32
33. 10. Performance monitoring with top and free Tuning systems is very, very involved and an almost full time job. top – watch Tasks (top left) and free memory, q quits, h for help free – shows free memory, more readable with free –m df - look at your devices, e.g. df -hT When Linux runs out of memory it will start killing processes, beware Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 33
34. 10.1 glances If in doubt, use glances, it is very good. install via apt-get update && apt-get install -V glances 10.2 process status ps -e or ps -ef or ps -e --forest Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 34
35. 11. Shutting down, doing it properly sudo shutdown –h 5 - halts the system sudo shutdown –r 2 - reboots the system sudo shutdown –c - cancel the shutdown Use these instead of the halt and reboot commands. Don’t just unplug the power, or you will eventually break your Linux system. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 35
36. 12. Clever things with Linux, using the GUI remotely X clients and X servers (1984 - MIT, now seen as X11 - version 11) ssh to the server with the -XC options from Linux then invoke synaptic or Firefox. Windows systems need to have an X client running (Xming or Cygwin). Macs might need security options fixing, for more modern systems see XQuartz project. The process load is on the Linux system, not the client or your PC/laptop, etc., Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 36
37. 13. Lost your Linux system? Do this only on your home network, ideally, not anywhere else. 13.1 Install zenmap and nmap apt-get update && apt-get –y –V install zenmap Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 37
38. 13.2 Scan the whole network (everything) from the CLI nmap –sP <IP range/24) e.g. nmap -sP 192.168.1.0/24 or nmap -sn 192.168.1.* or nmap -sP 192.168.1.1-255 13.3 Who am I? Find your own IP address by typing, ifconfig (old way) or ip a Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 38
39. 14. Linux Resources and links https://www.ibm.com/developerworks/library/l-lpic1-map/index.ht ml https://training.linuxfoundation.org/linux-courses https://www.netacad.com/campaign/linux-essentials3 https://www.edx.org/learn/linux https://www.linuxjournal.com/content/getting-help-linux-part-1-ma n-pages Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 39
40. 15. Summary of proper system management 1. Install the operating system. 2. Reboot. 3. Do an update/upgrade. 4. Reboot 5. Add any additional accounts. 6. Add any other apps, as required. 7. Check log files and performance NB: Use apt-get, etc to install programs and apps, any other way might break your system. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 40
41. Fini For additional material and answers see the FAQs Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 41
42. Frequently asked questions (FAQs): Q: Where are the slides kept? A: These are just draft ones, but the final version will always be at speakerdeck as BrianLinuxing. https://speakerdeck.com/brianlinuxing Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 42
43. Q: Why use the command line interface (CLI) when the Graphical user interface (GUI) is easier. A: The command line interface is used extensively in cloud computing, it is a desirable skill to have, not obvious and a little tricky at times but once it’s been explained it becomes incredibly powerful. The GUI is a simple interface not dissimilar to Windows, and fairly intuitive, it really doesn’t need much explaining, if at all. The CLI is what people really want to learn and ask about! Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 43
44. Q: How does TCP/IP work? A: TCP/IP is an immensely complex network protocol, but from our point of view we just need to know if you plug in a device it will request a TCP/IP address. That address is supplied by a DHCP server. In most instances that will be your home or office router. Q: What does DHCP mean? A: Dynamic Host Configuration Protocol Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 44
45. Q: Where can I learn more? Google is a good starting place, but many of the articles on the web are over-elaborate for beginners. The forums can be useful at times. Q: Isn't Linux too complicated to learn? Learning Linux is no more complicated than becoming familiar with another language or mastering the art of car driving. It takes patience, a degree of persistence but the rewards are immense. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 45
46. Q: What should I do now? Spent time reading, tinkering and if you ruin the Linux's file structure then you can always recreate it using the instructions in Linux 101, 102 or 104. Q: My commands never work under Linux on the command line. A: Linux is case sensitive, take extra care. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 46
47. Q: What does && and all of those funny Linux symbols do? A: They are called chaining operators, see https://www.tecmint.com/chaining-operators-in-linux-with-practical- examples/ Q: What else? Twitter is very useful, I am on there as @BrianLinuxing ! Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 47
48. Q: I need help, what do I do? A: Type, man <linux command> as a starter or typically <linux command> --help Info <linux command> or help Q: You didn’t answer my question. A: Linux is a complex operating system and can’t be rushed! Self study is always useful :) Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 48
49. Q: Why is the Penguin the symbol of Linux? A: It was suggested, overall, by Larry Ewing, Wiki has more details https://en.wikipedia.org/wiki/Tux_(mascot) Q: I have many, many more questions where should I go? A: Let Google be your friend in this case :) Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 49
50. Every journey begins with a single step Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 50
51. The End Thank you for participating and if you enjoyed the event, slides, etc. then please leave a nice comment on Twitter. Linux 103 © Brian Byrne, 2019. Twitter:@BrianLinuxing Email: BrianLinuxing@gmail.com 51