polish some course slides and reorder

linux_toolkit_2021/index.html

@@ -17,7 +17,7 @@ class: center, middle
 
 ---
 
-# We will see
+# We will see TODO
 
 ...a short **Bash** introduction, to get the necessary intuition for what most tools in this course do.
 
@@ -34,14 +34,16 @@ Reduce unknown unknowns (`what's available?`, `what do I search for?`, etc).
 
 Give a rough intuition for what classic Linux tools can do.
 
-Provide pointers for where to learn the tools.
-
 Learn vocabulary.
 
-Non-goal: teach you how to use the tools - I would love to, but we don't have time!
+Provide pointers for where to learn the tools.
+
 
 ---
 
+# example: a download filer
+
+Displays the most recently downloaded file and asks what to do with it
 
 ```bash
 file=$(ls -tp1 ~/Downloads | grep -v "/$" | head -1)
@@ -53,31 +55,30 @@ choice=$(echo $dirs | rofi -dmenu -sep ',' -p "move '$file' where? ")
 mv ~/Downloads/"$file" "$choice"
 ```
 
-safe the above in `/home/nils/filer.sh` and add a few lines of text in `~/.xbindkeysrc`:
+Save the above in `/home/nils/filer.sh` and add a few lines of text in `~/.xbindkeysrc`:
 
-```
+```bash
 "bash /home/nils/filer.sh"
   control+shift+f
 ```
 
 ---
 
-# How to use this talk
+# How to use this talk TODO
 
 - pick and choose the tools that seem interesting to you and try to learn them
 - come back to the slides and use them as a glossary for unknown words
-- ...or just be amused with what people come up with
 
 ---
 
-# Some philosophy
+# Some philosophy before Bash
 
 Many of the classical Linux tools adhere to the "UNIX principle":
 
 <blockquote>Do one thing and do it well.</blockquote>
 
-In a wider, non-programming sense: It's useful to  
-learn things that are small, orthogonal, and compose.
+This usually implies that they are built with composability in mind.
+We like that because it means we learn more things by doing less.
 
 ---
 
@@ -88,7 +89,7 @@ Related words: terminal, terminal emulator, shell, command line, ...
 <img src="images/bash.png" width="50%">
 
 In a nutshell:  
-Bash is a tool that let's you interact with your computer via text.
+Bash is a tool that let's you interact with your computer via text commands.
 
 **Try it out:** Open a terminal (just search for `Terminal` in your launcher)
 
@@ -99,15 +100,18 @@ Bash is a tool that let's you interact with your computer via text.
 Bash let's you interact with your computer by typing commands.
 
 There are **many** commands. Some examples:  
-`ls`, `pwd`, `echo`, `cd`, `mv`, `sleep`, `alias`, ...
+`ls`, `pwd`, `cd`, `echo`, `mv`, `cat`, `alias`, ...
 
 Some commands are built into Bash, others can be downloaded.
 
 Some commands are really just programs: try typing `firefox` and hitting Enter if you have it installed.
 
+Most commands take options that modify their default behavior.  
+`df` versus `df -h`
+
 ---
 
-# Filesystem basics
+# Basics: Taking a Walk
 
 List files and show where we are:
 
@@ -116,10 +120,10 @@ ls
 pwd
 ```
 
-Enter or leave directories:
+Enter and leave directories:
 
 ```bash
-cd my_folder
+cd linuxdaysDemo
 cd ..
 cd /home/nils/Desktop
 cd ~/Desktop
@@ -129,14 +133,13 @@ cd ~/Desktop
 
 # Bash terminology
 
-**terminal** is the window in which bash runs.
-
-bash is a kind of **shell**. there are others!
-
+The **terminal** is the window in which bash runs.
 
-<img src="images/terminal_old.webp" alt="https://www.reddit.com/r/raspberry_pi/comments/6se1qy/old_terminal_connected_to_my_pi_emulating_a_modem/" width="60%">
+Bash is a kind of **shell**. There are others (I use Zsh).
 
 
+<img src="images/terminal_old.webp" alt="https://www.reddit.com/r/raspberry_pi/comments/6se1qy/old_terminal_connected_to_my_pi_emulating_a_modem/" width="60%">  
+An actual terminal
 
 
 ---
@@ -145,7 +148,8 @@ bash is a kind of **shell**. there are others!
 
 Bash can even be used as a (terrible) programming language, using commands like `for`, `if`, `while`, `[[` etc.  
 
-It also makes use of special constructs that aren't commands (e.g. arithmetic expansion: `echo $((5+3))`)
+It also makes use of special constructs that aren't commands  
+(e.g. arithmetic expansion: `echo $((5+3))`)
 
 We'll only bother with `|` and `>` ("piping" and "redirecting").
 
@@ -163,35 +167,64 @@ Both redirect command output:
 
 ---
 
-# bash summary
+# Shell scripts
 
-bash is a different way of interacting with your system
+Shell scripts are just textfiles.
+We can put commands into them and then execute them all at once.
 
-bash runs in your terminal.
+Let's use the editor **nano** to create a file:
 
-bash is a shell. there are others: Zsh, fish, Dash, csh
+```bash
+nano ~/betterCd.sh
+```
+
+(inside nano:)
+```bash
+#!/bin/sh
+cd "$1"
+ls
+```
+
+Exit nano by pressing Control-o, Enter, and Control+x.  
+Then execute:
+
+````bash
+. ~/betterCd.sh ~/Documents
+```
 
-resources: 
+If you want, add `alias c='. ~/betterCd.sh'` to the file `~/.bashrc`.
+
+---
+
+# Bash Summary
+
+Bash is a different way of interacting with your system
+
+Bash runs in your terminal.
+
+Bash is a shell. there are others: Zsh, fish, Dash, csh
+
+Resources: 
 - our bash guide (https://thealternative.ch/guides/bash.php)
 - Lhunath and GreyCat's bash guide (http://mywiki.wooledge.org/FullBashGuide)
 
 ---
 
-# bash power
+# Teaser
 
 Move all `.png` files from Downloads to Images:  
 ```bash
-mv ~/Downloads/*.png ~/Images`
+mv ~/Downloads/*.png ~/Images
 ```
 
-go to our images, make a new directory, and move newest five images there:
+Go to our images, make a new directory, and move newest five images there:
 ```bash
 cd ~/Images
 mkdir newImages
 ls -1t *.png | head -5 | xargs -I {} mv {} newImages
 ```
 
-rename all images in a folder to `*_with_family`:  
+Rename all images in the current folder to `*_with_family`:  
 ```bash
 for file in *.png; do
         mv "$file" "$file_with_family"
@@ -200,23 +233,38 @@ done
 
 ---
 
+# Some final tips
+
+Use the Tab key for autocompletion (hit twice for all options)
+
+Control+c terminates the current command
+
+You can recall recently used commands by using the arrow keys.
+
+Sometimes you don't know how to use commands. `man command` can help with that.  
+You can search it with /, and quit it with Q.
+
+---
+
 class: center, middle
 
 # Tool Galore
 
-We will now talk about multiple tools and how to combine them using bash (mostly).
+We will now talk about multiple tools and how to combine them.
 
 ---
 
 # Scripting Languages
 
-bash is not ideal as a programming language.for more complex jobs,a real programming language is needed.
+Bash is not suited for programming.  
+For more complex jobs, a real programming language is needed.
 
-two main choices:  
-- Python (recommended for beginners)
-- Ruby (only if you already know programming; compact syntax)
+Two common choices:  
+- **Python**: Recommended for beginners. Lots of built-in functionality.
+- **Ruby**: If you already program. Compact syntax & metaprogramming.
+
+These fill niches that bash doesn't, and are still close to the system.
 
-these fill niches that bash doesn't, but are still close to the system.
 
 <img src="images/polygon.png" width="50%">
 
@@ -224,13 +272,14 @@ these fill niches that bash doesn't, but are still close to the system.
 
 # Notifications
 
-typically linux has a notification demon integrated.
+Typically, linux has a notification deamon integrated.
 
 ```bash
 notify-send "Hello"
 ```
 
-this is often useful for things that you want to run in the background.  
+This is often useful for things that you want to run in the background.  
+
 Example: Timer
 
 ```bash
@@ -241,20 +290,21 @@ sleep 300; notify-send "Time is up!"
 
 # Rofi
 
-can be used to display a list of things  
+Can be used to display a list of things  
 and then let's us choose one of them.
 
 ```bash
-echo "one\ntwo\nthree" | rofi -dmenu
+echo "one,two,three" | rofi -sep ',' -dmenu
 ```
 
-on its own is not useful, but can serve as a powerful launcher when combined with other things:  
+Rofi's dmenu mode on its own is not useful, but can serve as a powerful launcher  
+when combined with other commands:  
 
 ```bash
-ls -1 ~/Documents/books/*.pdf | rofi -dmenu | xargs -I {} evince {}
+ls -1 ~/books/*.pdf | rofi -dmenu | xargs -I {} xdg-open {}
 ```
 
-https://github.com/davatorium/rofi
+See: https://github.com/davatorium/rofi
 
 ---
 
@@ -262,32 +312,39 @@ https://github.com/davatorium/rofi
 
 A **keydeamon**! Let's us configure keyboard shortcuts.
 
-in file `~/.xbindkeysrc`:
+In file `~/.xbindkeysrc`:
 
 ```bash
 "notify-send test"
   control+t
 
-"ls -1 ~/Documents/books/*.pdf | rofi -dmenu | xargs -I {} evince {}"
+"ls -1 ~/books/*.pdf | rofi -dmenu | xargs -I {} xdg-open {}"
   control+Mod1+b
 ```
 
-<img src="images/booklauncher.png">
-
 ---
 
 
 ```bash
+# pick most recently downloaded file. Store in a variable.
 file=$(ls -tp1 ~/Downloads | grep -v "/$" | head -1)
 dirs='Images,Videos,Documents,Documents/books,DELETE,OPEN'
-choice=$(echo $dirs | rofi -dmenu -sep ',' -p "move '$file' where? ")
+
+# Display rofi to choose from actions. Store in variable.
+choice=$(echo $dirs | rofi -dmenu -sep ',' -p "move '$file' to: ")
 [[ "$choice" = "" ]] && exit
+
+# if the choice was DELETE, then delete and exit
 [[ "$choice" = DELETE ]] && rm ~/Downloads/"$file" && exit
+
+# if the choice was OPEN, then open and exit
 [[ "$choice" = OPEN ]] && xdg-open ~/Downloads/"$file" && exit
+
+# otherwise move the file
 mv ~/Downloads/"$file" "$choice"
 ```
 
-safe the above in `/home/nils/filer.sh` and add a few lines of text in `~/.xbindkeysrc`:
+Save the above in `/home/nils/filer.sh` and add a few lines of text in `~/.xbindkeysrc`:
 
 ```
 "bash /home/nils/filer.sh"
@@ -299,34 +356,64 @@ safe the above in `/home/nils/filer.sh` and add a few lines of text in `~/.xbind
 
 # grep
 
-a command to look for **regular expressions**.
+A command to look for **regular expressions** (commonly just "regex").
+
+Think of regexes as being text patterns on steroids:
 
-think of regular expressions as being text patterns on steroids:
+`grep -E "^[0-9]" data.csv` prints all the lines starting with a number
 
-`grep "^[0-9]" data.csv` prints all the lines starting with a number
+We can put multiple greps together to chain filters:
 
-we can try a multiple greps together to chain filters:
+TODO
 
-<img src="images/">
-<img src="images/">
-<img src="images/">
+https://www.rexegg.com/
+
+---
+
+#grep
+
+Hot tip: Put `alias grep='grep -E'` into `~/.bashrc`.  
+
+`-E` switches to "extended regular expressions".
+
+Unfortunately, there are lots of regex standards with minor differences.  
+Stick with one and don't worry about it (until you do).
+
+---
+
+#grep
+
+Hot tip: Put `alias grep='grep -E'` into `~/.bashrc`.  
+
+`-E` switches to "extended regular expressions".
+
+Unfortunately, there are lots of regex standards with minor differences.  
+Stick with one and don't worry about it (until you do).
+
+<img src="images/xkcd.png" width="50%">
+<p style="color: grey;">https://xkcd.com/1171/</p>
 
 ---
 
 # sed
 
-**s**tream **ed**itor
+The **s**tream **ed**itor.
 
-this tool can search for regular expressions like we did with `grep`,  
-and perform various operations on each output line separately
+This tool can search for regular expressions   [and more] like we did with `grep`,  
+and perform various operations on the matched lines.
+
+Example: Delete all comments from a file
+```bash
+sed -E 's/^#.*//g' file.py
+```
 
 ---
 
 # find
 
-a general purpose tool for finding various files according to search filters.
+A general purpose tool for finding various files according to search filters.
 
-especially nice if used with xargs-style option or regular expressions:
+Especially nice if used with the `-exec` option or regular expressions:
 
 Remove all files (`-type f`) that end in .php (`*.php`):  
 ```bash
@@ -342,11 +429,11 @@ find ~/Documents -type f -exec grep -l "//.*TODO" {} \;
 
 # file conversion
 
-sometimes you want to convert between similar file formats. there are a lot of tools for this. most are specific for some kind of file content.here are some common ones:
+Sometimes you want to convert between similar file formats. there are a lot of tools for this. most are specific for some kind of file content.here are some common ones:
 
 - `ffmpeg` for audio and video
 - `pandoc` for many hierarchical text formats (mark down, html, latex)
-- `pandoc` for image files
+- `convert` for image files. Also known as ImageMagick.
 
 <hr>
 
@@ -363,61 +450,92 @@ done
 
 # wget
 
-mirror webpage
+A general purpose download tool.
 
+Mirror a webpage:
 ```bash
 wget --mirror --convert-links --page-requisites \
 --no-parent -e robots=off https://thealternative.ch
 ```
 
+Download all pdf files:
+```bash
+site=https://people.inf.ethz.ch/suz/teaching/252-0210.html
+wget --no-parent -r -l 1 -A .pdf $site
+```
 
 ---
 
 # git
 
-Git is a version control system: Keep track of who changed what, when and why, and revert changes easily. 
+Git is a version control system:  
+Keep track of who changed what, when and why, and revert changes easily. 
 
+Clone our courses repository:
 ```bash
-git init
-git add *
-git commit -m "Initial commit"
-git remote add git@gitlab.ethz.com/thealternative/courses.git
-git push -u origin --all
+git clone https://gitlab.ethz.ch/thealternative/courses.git
+```
+
+When you just want a pull changes:
+```bash
+git stash
+git pull
 ```
 
 *Visit the git course next week!*
 
+Also recommended: Git for ages 4 and up (video)
+
 ---
 
 # ssh
 
-`Euler` is an ETH supercomputer:
+SSH lets us connect to servers and execute commands there.
+
+Connect to `Euler`, an ETH supercomputer:
 
 ```bash
 ssh nilsl@euler.ethz.ch
 ```
 
-Connect with SSH and execute commands in the console of the server.
+We land in a bash shell and can execute commands.
 
+The command **scp** let's you copy files between the server and your PC.
+There's also **rsync** which is a more advanced way of copying files.
 ---
 
 # tmux
 
-Execute long-running processes in the background while your terminal is closed. Especially useful in combination with SSH.
+Execute long-running processes in the background while your terminal is closed.
+Especially useful in combination with SSH.
 
 ```bash
-tmux new -s new_session
-tmux attach new_session
+ssh nilsl@euler.ethz.ch
+tmux new -s my_session
+tmux attach my_session
 ```
 
+Do some stuff, close the window, then come back later.
+
+```bash
+ssh nilsl@euler.ethz.ch
+tmux attach my_session
+```
+
+An older but more widely available alternative to tmux is **screen**
+
 ---
 
-# xdotools
+# xdotool
+
+
+Automates key presses and mouse movements.
+Useful for repetitive user interface stuff.
 
-Automate key presses & mouse movements.
+In a browser, copy the link of the current tab and then close it.
 ```
-xdotool key ctrl+c key alt+Tab key ctrl+v
-xdotool mousemove 20 100 click 1 sleep 2 mosemove 100 20
+"xdotool key --delay 300 F6 ctrl+c ctrl+w"
+  F10
 ```
 
 ---
@@ -431,7 +549,8 @@ Categories:
 - text processing (like vim, sed, bash)
 - file conversion (like ffmpeg, pandoc, convert)
 - searching (like sed, grep, find)
-- glue (like xdotools, rofi, xbindkeys, notify-send, python, bash)
+- scripting (like xdotools, rofi, xbindkeys, notify-send, python, bash)
+- interfaces
 
 ---
 
@@ -439,7 +558,7 @@ Categories:
 
 **stow** lets you manage config files easily.  
 **ranger** is a console-based file manager.  
-**i3** is an alternative window-manager.  
+**i3** is an alternative window manager.  
 **borg** is a backup tool.  
 **nano** is an easy to use console text-editor.
 **rsync** to copy files between machines.