Building Command-line Applications in Ruby

Slides that accompany a lightening talk from RedSnake Philly 2013 [0] on building command-line applications in Ruby with Thor [1], Cucumber [2], Aruba [3], and Riak CS [4]. The example Riak CS command-line application used in the presentation can be found here [5].

[0] http://redsnakephilly.org/
[1] http://whatisthor.com/
[2] http://cukes.info/
[3] https://github.com/cucumber/aruba/
[4] http://basho.com/riak-cloud-storage/
[5] https://github.com/hectcastro/riakcs/

Transcript

1. Building Command-line Applications in Ruby
2. Hector Castro Technical Evangelist at Basho @hectcastro
3. Types of Command-line Interfaces
4. $ # non-interactive example $
5. $ # non-interactive example $ mv deal-with-it.gif ~/gifs $
6. $ # interactive example $
7. $ # interactive example $ ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/Users/hector/.ssh/id_rsa):
8. $ # interactive example $ ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/Users/hector/.ssh/id_rsa): Created directory '/Users/hector/.ssh'. Enter passphrase (empty for no passphrase):
9. $ # interactive example $ ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/Users/hector/.ssh/id_rsa): Created directory '/Users/hector/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again:
10. $ # interactive example $ ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/Users/hector/.ssh/id_rsa): Created directory '/Users/hector/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /Users/hector/.ssh/id_rsa. Your public key has been saved in /Users/hector/.ssh/id_rsa.pub.
12. Checklist for a Non-interactive CLI
13. $ # reduce interactivity and unnecessary output $
14. $ # reduce interactivity and unnecessary output $ mv deal-with-it.gif ~/gifs $
15. $ # emit accurate exit status $
16. $ # emit accurate exit status $ mv deal-with-it.gif ~/gifs $
17. $ # emit accurate exit status $ mv deal-with-it.gif ~/gifs $ echo $? 0 $
18. $ # emit accurate exit status $
19. $ # emit accurate exit status $ mv cats.gif ~/gifs mv: rename cats.gif to /Users/hector/gifs: No such file or directory $
20. $ # emit accurate exit status $ mv cats.gif ~/gifs mv: rename cats.gif to /Users/hector/gifs: No such file or directory $ echo $? 1 $
21. $ # have a concise name $
22. $ # have a concise name $ svn co file:///does/anyone/use/me/anymore answer A answer/nope.txt Checked out revision 20. $
23. $ # respect single and multi-letter options $
24. $ # respect single and multi-letter options $ heroku -h << HELP CONTENT >> $
25. $ # respect single and multi-letter options $ heroku -h << HELP CONTENT >> $ heroku --help << HELP CONTENT >>
26. $ # ensure that you provide a --help option $
27. $ # ensure that you provide a --help option $ dd -h dd: unknown operand -h $
28. $ # ensure that you provide a --help option $ dd -h dd: unknown operand -h $ dd --help dd: unknown operand --help
29. $ # use STDOUT correctly $
30. $ # use STDOUT correctly $ curl https://api.github.com/users/hectcastro > hector.json
31. $ # use STDOUT correctly $ curl https://api.github.com/users/hectcastro > hector.json $ cat hector.json | jq ".name" "Hector Castro"
32. $ # use STDERR correctly $
33. $ # use STDERR correctly $ curl joker://api.github.com/users/hectcastro curl: (1) Protocol joker not supported or disabled in libcurl
34. $ # use STDERR correctly $ curl joker://api.github.com/users/hectcastro curl: (1) Protocol joker not supported or disabled in libcurl $ curl joker://api.github.com/users/hectcastro > error.txt 2>&1
35. $ # use STDERR correctly $ curl joker://api.github.com/users/hectcastro curl: (1) Protocol joker not supported or disabled in libcurl $ curl joker://api.github.com/users/hectcastro > error.txt 2>&1 $ cat error.txt curl: (1) Protocol joker not supported or disabled in libcurl