Command Line Interface

Text-based interface.

Notes

Commonly forgot tricks

• > for override, >> for append
• echo $PATH | tr ':' '\n'
  • Echo all path per line

Network related

• curl -d '{"key":"value"}' https://domain.com/path/to/file
  • POST request

Resources

• The Linux Command Line for Beginners | Ubuntu
  • If you don't know what are cd, ls, and grep, this might be where to start
  • Ultimately, learn by trial and error
• Command Line Interface Guidelines
  • A guide to building command line interfaces, very detailed and informative
  • The philosophy of a good CLI and the guidelines to follow when building one
• The terminal | furbo.org
  • A long list of commands in Unix and Mac

Sites

• Modern Unix
  • A collection of modern alternatives for some classic Unix commands
• Explain Shell
  • Visually breaking down and explaining a shell command
• tldr.sh
  • Simplified and community-driven manual
• Command Line Fu
  • Searchable list of community recorded command line gems
• Pure sh bible
  • List of methods doing various tasks using only built-in POSIX sh features
• cheat.sh
  • Quick references for common CLI commands

Links

• What is the SSH randomart image for?
  • There is a "randomart image" from ssh-keygen from the terminal
  • Support comparing host keys visually, especially recognizing host keys that have been changed
• CLI tools in the Python standard library | Simon Willison (HN)
  • Server current directory over HTTP: python -m http.server 8000
  • Pretty-print JSON: echo '{"key": "value"}' | python -m json.tool
  • tokenize, base64, random, calendar, etc.
• What does 2>/dev/null means?
  • > means redirect, 2> file means redirect stderr to file, /dev/null is the null device
• Entering text in the terminal is complicated | Julia Evans (HN)
  • The baseline:
    • No arrows, no history
    • Ctrl+W delete word, Ctrl+U delete line
    • stty -a list what's supported in the terminal
  • readline:
    • Up arrow to previous command
    • Ctrl+E or End, Ctrl+A or Home, Ctrl+left/right back/forward 1 word
    • Ctrl+R to search history
    • rlwrap python to wrap a program with readline support
• Terminal Colours are Tricky | Julia Evans
  • 16 ANSI colours, configuring colours, problem of colours in vim, etc.
• "Rules" that terminal programs follow | Julia Evans (HN)
  • Ctrl-C, Ctrl-D, Ctrl-W, 16 ANSI colors, - for stdin/stdout
• What does "2>&1" mean?
  • 2 refers to file descriptor 1 (stdout) and 2 (stderr) redirect (>) to &1 file descriptor 1 (stdout)