Command Line Applications in Ruby
Twitter: @krzkot
Github: lis2
Email: kotlarek.krzysztof@gmail.com
What is a good application?
- Have a clear an concise purpose
- Easy to use
- Helpful
- Plays well with others
- Has sensible defaults but is configurable
- Installs painlessly background
Command line app
~ cowsay "JNS Meetup"
____________
< JNS Meetup >
------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||~ cowsay -e '--' "JNS Meetup"
____________
< JNS Meetup >
------------
\ ^__^
\ (--)\_______
(__)\ )\/\
||----w |
|| ||Cowsay
~ cowsay --help
/usr/local/bin/cowsay version [unknown] calling Getopt::Std::getopts
running under Perl version 5.18.2.
Usage: cowsay [-OPTIONS [-MORE_OPTIONS]] [--] [PROGRAM_ARG1 ...]
The following single-character options are accepted:
With arguments: -e -f -T -W
Boolean (without arguments): -b -d -g -h -l -L -n -N -p -s -t -w -y
Options may be merged together. -- stops processing of options.JnsSay
OptionParser
require 'optparse'
options = {}
OptionParser.new do |opts|
opts.on("-u", "--user [USER]") do |u|
options[:user] = u
end
opts.on("-m", "--message [MESSAGE]") do |m|
options[:message] = m
end
end.parse!
JnsSay::Say.new(options[:user], options[:message]).displayHelp
require 'optparse'
options = {}
OptionParser.new do |opts|
opts.banner = "Usage: jns_say.rb -u lis2 -m blablabla"
opts.on("-u", "--user [USER]", "User name - top part of your output") do |u|
options[:user] = u
end
opts.on("-m", "--message [MESSAGE]", "Message - bottom part of your output") do |m|
options[:message] = m
end
end.parse!
JnsSay::Say.new(options[:user], options[:message]).display~ lib/jns_say.rb -h
Usage: jns_say.rb -u lis2 -m blablabla
-u, --user [USER] User name - top part of your output
-m, --message [MESSAGE] Message - bottom part of your outputgem-man
The gem man command can be used to display a man page for an installed RubyGem. The man page must be included with the gem
Default Behaviour
options = {
user: "Anonymous"
}
OptionParser.new do |opts|
...
endConfiguration
options = {
user: "Anonymous"
}
CONFIG_FILE = File.join(ENV['HOME'], '.jns_say.yml')
if File.exists?(CONFIG_FILE)
options.merge!(YAML.load_file(CONFIG_FILE))
end
OptionParser.new do |opts|
...
endSave default config file
options = {
user: "Anonymous",
message: "Default message"
}
CONFIG_FILE = File.join(ENV['HOME'], '.jns_say.yml')
if File.exists?(CONFIG_FILE)
options.merge!(YAML.load_file(CONFIG_FILE))
else
File.open(CONFIG_FILE, 'w') do |file|
YAML::dump(options, file)
end
STDERR.puts "Initialized configuration file in #{CONFIG_FILE}"
end
OptionParser.new do |opts|
...
endPlays well with others
~ ls -1
Applications
Books
Desktop
Documents
Downloads
Dropbox
Library
Movies
Music
Pictures
Public
Sites
Synology
ansible-playbook
bin
dotfiles
go
presentations
rails
ssh~ ls -1 | sort -r
ssh
rails
presentations
go
dotfiles
bin
ansible-playbook
Synology
Sites
Public
Pictures
Music
Movies
Library
Dropbox
Downloads
Documents
Desktop
Books
ApplicationsNAME
sort - sort lines of text files~ ls
Applications Desktop Downloads Library Music
Books Documents Dropbox Movies Pictures ~ ls | sort -r
ssh
rails
presentations
go
dotfiles
bin
ansible-playbook
Synology
Sites
Public
Pictures
Music
Movies
Library
Dropbox
Downloads
Documents
Desktop
Books
Applicationsoptions = {}
OptionParser.new do |opts|
opts.banner = "Usage: jns_say.rb -u lis2 -m blablabla"
opts.on("-u", "--user [USER]", "User name - top part of your output") do |u|
options[:user] = u
end
opts.on("-m", "--message [MESSAGE]", "Message - bottom part of your output") do |m|
options[:message] = m
end
if STDOUT.tty?
options[:format] = 'pretty'
else
options[:format] = 'csv'
end
end.parse!Colors
require 'rainbow'
puts Rainbow("this is red").red + " and " + Rainbow("this on yellow bg").bg(:yellow)
puts Rainbow("even bright underlined!").underline.bright
Tables
require 'terminal-table'
rows = []
rows << ['One', 1]
rows << ['Two', 2]
rows << ['Three', 3]
table = Terminal::Table.new :rows => rows
# > puts table
#
# +-------+---+
# | One | 1 |
# | Two | 2 |
# | Three | 3 |
# +-------+---+Progress bar
require 'progress_bar'
bar = ProgressBar.new
100.times do
sleep 0.1
bar.increment!
end
[####################################### ] [ 59.00%] [00:06]Command line suite
~ git commit
~ git push~ git commit -h
usage: git commit [options] [--] <pathspec>...
-q, --quiet suppress summary after successful commit
-v, --verbose show diff in commit message template
Commit message options
...~ git push -h
usage: git push [<options>] [<repository> [<refspec>...]]
-v, --verbose be more verbose
-q, --quiet be more quiet
--repo <repository> repository
--all push all refs
--mirror mirror all refs
--delete delete refs
--tags push tags
...Command line suite
require 'gli'
include GLI::App
flag :f
command :new do |c|
c.flag :priority
c.switch :f
c.action do |global_options,options,args|
global_options[:f]
options[:priority]
options[:f]
args
# suite.rb -f test.txt new -f -priority 200require 'gli'
include GLI::App
flag [:f, :filename]
command :new do |c|
c.flag :priority
c.switch :f
c.action do |global_options,options,args|
global_options[:f]
options[:priority]
options[:f]
args
# suite.rb -f test.txt new -f -priority 200
# suite.rb --filename test.txt new -f -priority 200require 'gli'
require 'hacer'
include GLI::App
program_desc 'A simple todo list'
flag :f
command :new do |c|
c.desc = "description of priority flag"
c.flag :priority
c.desc = "description of filename switch"
c.switch [:f, :filename]
c.action do |global_options,options,args|
global_options[:f]
options[:priority]
options[:f]
argsresources
