Daily Log

2021-03-04

• Organizational Blah

  • Plan for Summer 2021

  • Cloud Computer, SSH Login

• Discussion

2021-03-05

Cheat Sheets

• Bash Help Sheet

• Default Keyboard Shortcuts for Bash

From Linux Basics (PDF) …

• Bausteine von Unix und Linux

  5-7, 9-16

• Die Shell (Bash - “Bourne Again Shell”)

  36-45, 58-61, 63, 64

2021-03-18

From Linux Basics (PDF) …

• Das Filesystem

  Es ist wichtig, im Filesystem navigieren zu können. Die Basic Tools müssen sitzen (cd, ls, pwd, mkdir, rm, cp, mv, etc.). (Dazu muss man natürlich verstehen, was Files, Directories etc. sind.)

  Das Permission-Thema ist extrem wichtig, und man kann damit rechnen, dass zur Prüfung ein paar trockene Fragen zu dem Thema kommen.

  • Pfade: 67-71

  • Directories: 72-76

  • Symbolische Links: 77-79

  • Directory Listings (ls): 84-87

  • Kopieren und Verschieben (cp und mv): 88-91

  • Owner, Permissions: 92-97, 100

2021-03-26

• Das Filesystem

  • Permissions

    • Die umask: 98-99

    • Tools für Permissions: 100

    • Set-UID Bit: 101

    • Sticky Bit: 102

  • Das find Command: 105-109

• Tools für Textfiles: 113ff.

  Das Kapitel wurde ansatzweise durchgegangen - jedes Tool. Wichtig ist, zu verstehen,

  • dass die Tools von Standard Input lesen, auf Standard Output schreiben (und auf Standard Error Fehler und Debug-Messages schreiben).

  • dass diese und andere Tools durch die Benutzung von Standard Input und Standard Output in der Pipe

• IO Redirection und Pipes: 133ff.

  Dieses Kapitel wurde in einem mit den Tools durchgemacht, ansatzweise.

  Wichtig ist mir, dass die Wirkungsweise der Pipe verstanden wird, und dass man Tools mit ihrer Hilfe verknüpfen kann.

2021-04-15

• Aufwärmen

  • SSH Public Key Authentication (see here for SSH topics)

  • Das verdammte Directory eines fremden Users, das ein File drin hat, das ich aus dem Directory nicht löschen darf.

  • Abschluss des Linux/Shell Kapitels: Fragerunde

• Python Setup

  • Python Installation

  • Visual Studio Code for Python Programming

• Python Intro

  • Python: The Language Fundamentals

2021-04-21

Git Intro

Download and Installation

• Git for Windows

• Git for MacOS

Github

• Private repository on Github: jfasch/FH-ECE-19

• Create Github account, and send it to jf@faschingbauer.co.at

• Clone the repository

  $ cd directory-where-i-have-my-ec-work
  $ git clone https://github.com/jfasch/FH-ECE-19.git
  

• If you are getting tired of entering a password for each repo transaction, you can always deploy a SSH public key to Github, and then re-clone using the SSH access method:

  $ git clone git@github.com:jfasch/FH-ECE-19.git
  

Python

Notebook Structure	Notebook Download
Basics Jupyter Notebook Syntax Batteries Tuple Unpacking for Key Value Map Syntax Comments vs Documentation Docstrings Multiline String (btw.) Variables Tuple Unpacking Assignment Details Datatypes Numbers Integer Numbers (Literals) Arithmetic Operators Wertebereich von Integers Strings Datatype Conversions Complex Datatypes Listen Dictionaries	Notebook: Datatypes

2021-04-29

• Raspi Lab Setup

  • Image preparation using script in our Github repo

  • Me being Doze admin, configuring static IPs

• GPIO demo, using an LED

• OneWire demo, using one of those DS18B20 sensors.

Topics of interest, from Group 2

• Exercise recap: Exercise: Digit to English Word

2021-05-10

Org Stuff

• Course documentation

  • Notebooks now maintained here (moved over from Github) (see here)

• Github

  • Repo made private

  • FH VPN? Gitlab?

Python: Functions

Course Material	Notebook Structure	Notebook Download
Functions Functions: Global and Local Scope (Livehacking Screenplay)	An Example Sidenote: Pure Beauty Parameters and Types Default Parameters Pitfalls Keyword Arguments	Notebook: Functions

2021-05-12

Python: Walk-Through Passing and Failing an Exam

Writing a checker for the exercise (live hacking).

Course Material	Notebook Structure	Notebook Download
(void)	Tuple Unpacking String Methods Strings vs. Bytes	Notebook: Checker Explanations

Further Information

• os.path module (from the Python docs)

• subprocess module (from the Python docs)

• Stackoverflow: Git file permissions on Windows

• Python Tutorial: Using Try/Except Blocks for Error Handling, by Corey Schafer

• Python Tutorial: OS Module - Use Underlying Operating System Functionality, by Corey Schafer

• Python Tutorial: Calling External Commands Using the Subprocess Module, by Corey Schafer

• Python 3.7: Encode String Method

2021-05-{19,20}

Course Material	Notebook	Notebook Download
File I/O Miscellaneous String Methods	2021-05-20 (G2) File I/O Reading File in One Big Swoop Reading File in Fixed Sized Chunks Reading File Line by Line Iterating a File String Methods (Needed to Implement the Exercise) str.strip(), str.rstrip(), str.lstrip() str.split()	Notebook: 2021-05-20 (G2)

Reiterating on Exercise

Exercise: Digit to English Word

• Hashbang: #!/usr/bin/python

  • (Student1): missing

    • Program is run as a shell script

    • Why does it take so long? Turns out that import is a screenshot command.

  • Anzhelika Chernykh: #!usr/bin/python

• (Student2)

  d = dict()
  d = {0: 'zero', 1: 'one', 2: 'two', 3: 'three',4: 'four',5: 'five', 6: 'six', 7: 'seven', 8:'eight', 9: 'nine'}
  

• (Student3)

  if __name__ == "__main__":
      main()
  

import argparse

In checker-digit …

• overcome those undescriptive IndexError messages when a user fails to pass the correct arguments.

• Optional argument: --python (a contribution to Doze users)

2021-05-21

Exercise digit (Once More)

(Exercise: Digit to English Word)

• Make it executable

  On Linux,

  $ chmod 755 digit
  $ git add digit
  

  On Doze (there is no such execute permissions),

  $ git update-index --chmod=+x digit
  

  (found on Stackoverflow)

• Windows: hashbang and CRLF massacre

  • “Executable” definition: .py vs. 755

  • 755 ⟶ hash bang

  • Windows CRLF: #!/usr/bin/python^M

  • Interpreter path: /usr/bin/python does not exist on Windows

  • \r\n massacre, especially inside hashbang line

• Linux: Why do I have to say, ./digit ?

Modules

• Modules and Packages

• What’s this?

  if __name__ == '__main__':
      ...
  

• Live-hack it: externalize students list into module

Encoding

• Encoding

• Re-iterate on exercise’s use when capturing stdout.

Notebook

Course Material	Notebook	Notebook Download
Modules and Packages Encoding	2021-05-21 Modules and Packages	Notebook: 2021-05-21

2021-06-01

sysfs GPIO: Blinking an LED

2021-06-07

Trial exam (see here)

Missing questions:

• stdin and stdout and their relationship to the pipe. stderr.

• SSH, password vs. key based authentication

• Python: what to ask?