missing.md

Sam's Take on the Missing Semester of Your CS Education

Inspired by The MIT CSAIL course by the same name.

• CLI intutition

  • --version (-V)
  • --verbose (-v)
  • Command-line flag conventions
    • Dashes
    • short vs long flags
      • Usually use long in scripts, save me a trip to the man page
    • Args vs options
    • double-dash
  • man vs --help
  • man page vs function page
  • Read the error message in full.
    • git status
  • Symlinks
    • --follow-symlinks

• Git intuition

  • Git != GitHub
  • https://missing.csail.mit.edu/2020/version-control/

• Env vars

  • .profile and rc scripts
  • PATH, PYTHONPATH/GOPATH/etc.
  • Shell vars are not the same!
  • sourceing stuff.
    • Installers will often ask you, or restart shell
  • Meaning and usage of: a=b cmd

• Writing portable scripts

  • Hashbang (chmod +x)
  • Use conventions!
    • Short/long flags
    • --help, --verbose
    • Your program should be quiet
    • Line breaks!
      • I'm weird and end lines in true
    • Warnings
    • stdout/stderr
    • Exit status
    • Say how to fix it
    • The limits of arguments
    • [Yy]* or [Nn]* in a loop
  • Shell scripts
    • Bash, POSIX sh, vs other sh for hashbang
    • set -o errexit -o pipefail -o noclobber -o nounset
    • cd "$(dirname "${0}")"
    • How to quote variables that could have spaces or dollars
      • Curlies and quotes "foo-${bar}-baz"
      • Nested quotes
      • Literals should be $'isn't this cool?'
    • IFS splitting
    • find -print0
    • if COMMAND justs tests the exit code!!
      • test and [ are just binaries whose exit code doesn't indicate error!
      • test -n, -z, -f
      • && and || operators vs -a and -o operators.
    • Defensive coding
      • Does file exist? If not, make it or give informative error
      • Does tool exist? if not, give informative error (give install command)
      • State management instead of imperative commands
    • How to parse flags
      • https://stackoverflow.com/a/33826763/1078199
        • Easy-ish
      • https://stackoverflow.com/a/29754866/1078199
        • Fancier. At this point, consider a real language.
    • When to use a real language
      • Compatability problems
      • Arcane syntax
  • Python script
    • click
    • To package or not to package (more than one machine, more than one use-case)
    • How to deal with deps
    • How to parse flags
    • Python API main vs other main

• Using the shell

  • https://missing.csail.mit.edu/2020/course-shell/
  • https://missing.csail.mit.edu/2020/shell-tools/
  • Whitespace
  • Diff between shell and exec (when to use sh -c)
  • Why sudo echo blah > file doesn't work.
    • echo blah | sudo tee file does
  • Ctrl+R
  • sudo !! or Ctrl+R Ctrl+A sudo
  • When to quote, always '' or $''
  • Ctrl+D
  • Ctrl+C/Ctrl+\
  • Using less
    • Keys: j, k, PageUp, PageDown, g, G, /
  • Using tmux

• Unix maintenance

  • alias, PATH, symlink-binaries, which, startup-scripts
  • Package management dumpster fire
    • Installing packages without root
    • brew/apt/yum/etc.
    • Language-level package manager
      • pip might not know about packages installed with apt
      • Binaries tho?
      • pip has more packages than apt
    • Nix
    • Installing from source

• Tools

  • find/fd
  • grep/rg
  • sed
  • jq/yq
  • xargs
  • pandoc
  • ffmpeg
  • https://missing.csail.mit.edu/2020/data-wrangling/
  • gnu make

• Markdown

  • Usage: doc-strings, README.md, Messenger (!)
  • Elements: lists, quotes, links, headings, bold, code blocks, code inline, LaTeX sometimes
  • Pandoc

• Zsh customization

• Interacting with the community

  • How to contribute to an open source project
    • Look for Contributing
    • File or find an issue
      • say you are working on a PR
    • Fork a repo (GitHub)
    • (do the fix)
    • Run tests
    • Submit a PR (GitHub)
    • Why try?
  • How to ask for help
    • Prior research
    • Short, Self Contained, Correct (Compilable), Example
      • Shorten all var-names, strings, and lists
      • http://sscce.org/
      • Live online code compiling (jsfiddle, sqlfiddle, TS playground, Rust playground, etc.)
      • Docker, if the problem is system dependent
        • https://stackoverflow.com/questions/51680479/multiprocessing-queue-fails-intermittently-bug-in-python
      • 80% of the time, this action actually helps you solve your own problem.
    • More details at the end
    • Check back frequently
    • GitHub specific:
      • File an issue
    • StackOverflow specific:
      • Know what questions are "off topic".
        • Overly broad questions of preference "which JS framework is best?" are usually considered off-topic.
      • Use tags, use comments, revise your original question to add info and stratigically bump.
    • IRC etiquette