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piotrmurach
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Description

Toolkit for developing sleek command line apps.

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TTY is a toolbox for developing beautiful command line clients in Ruby with a fluid interface for gathering input, querying terminal properties and displaying information.

Motivation

All too often libraries that interact with terminals create their own interface logic that gathers input from users and displays information back. Many times utility files are created that contain methods for reading system or terminal properties. Shouldn't we focus our energy on building the actual client?

Building terminal tools takes time. I believe that modular components put together in a single package with project scaffolding will help people build things faster and produce higher quality results. It is easy to jump start a new project with available scaffolding and mix and match components to create new tooling.

Features

  • Jump-start development of your command line app the Unix way with scaffold provided by teletype.
  • Fully modular, choose out of many components to suit your needs or use any 3rd party ones.
  • All tty components are small packages that do one thing well.
  • Fully tested with major ruby interpreters.

Installation

Add this line to your application's Gemfile to install all components:

gem 'tty'

or install a particular component:

gem 'tty-*'

And then execute:

$ bundle

Or install it yourself as:

$ gem install tty

Contents

1. Overview

TTY provides you with commands and many components to get you onto the path of building awesome terminal applications in next to no time.

To simply jump start a new command line application use

teletype
executable:
$ teletype new app

Move in to your new app, and then add more commands:

$ cd app
$ teletype add config

Throughout the rest of this guide, I will assume a generated application called

app
, that you are in the working directory of 'app/', and a newly created bare command
config
.

2. Bootstrapping

2.1
new
command

Running

teletype new [app-name]
will bootstrap an entire project file structure based on the bundler
gem
command setup enhanced by additional files and folders related to command application development.

For example, to create a new command line application called

app
do:
$ teletype new app

The output will contain all the files that have been created during setup:

Creating gem 'app'
    create app/Gemfile
    create app/.gitignore
    create app/lib/app.rb
    create app/lib/app/version.rb
    ...

In turn, the following files and directories will be generated in the

app
folder familiar to anyone who has created a gem beforehand:
▾ app/
├── ▾ exe/
│   └── app
├── ▾ lib/
│   ├── ▾ app/
│   │   ├── ▸ commands/
│   │   ├── ▸ templates/
│   │   ├── cli.rb
│   │   ├── command.rb
│   │   └── version.rb
│   └── app.rb
├── CODE_OF_CONDUCT.md
├── Gemfile
├── LICENSE.txt
├── README.md
├── Rakefile
└── app.gemspec

By convention the file

lib/app/cli.rb
provides the main entry point to your command line application:
module App
  class CLI < Thor
    # Error raised by this runner
    Error = Class.new(StandardError)

desc 'version', 'app version'
def version
  require_relative 'version'
  puts "v#{App::VERSION}"
end
map %w(--version -v) =&gt; :version

end end

This is where all your application commands and subcommands will be defined.

Teletype uses

Thor
as an option parsing library by directly inheriting from it.

And also by convention the

start
method is used to parse the command line arguments inside the
app
executable:
App::CLI.start

Run the new command with

--help
or
-h
flag to see all available options:
$ teletype new --help
$ teletype new -h

Execute

teletype
to see all available commands.

2.1.1
--author
,
-a
flag

The

teletype
generator can inject name into documentation for you:
$ teletype new app --author 'Piotr Murach'

2.1.2
--ext
flag

To specify that

teletype
should create a binary executable (as
exe/GEM_NAME
) in the generated project use the
--ext
flag. This binary will also be included in the
GEM_NAME.gemspec
manifest. This is disabled by default, to enable do:
$ teletype new app --ext

2.1.3
--license
,
-l
flag

The

teletype
generator comes prepackaged with most popular open source licenses:
agplv3
,
apache
,
bsd2
,
bsd3
,
gplv2
,
gplv3
,
lgplv3
,
mit
,
mplv2
,
custom
. By default the
mit
license is used. To change that do:
$ teletype new app --license bsd3

2.1.4
--test
,
-t
flag

The

teletype
comes configured to work with
rspec
and
minitest
frameworks which are the only two acceptable values. The
GEM_NAME.gemspec
will be configured and appropriate testing directory setup. By default the
RSpec
framework is used.
$ teletype new app --test=minitest
$ teletype new app -t=minitest

2.2
add
command

Once application has been initialized, you can create additional command by using

teletype add [command-name]
task:
$ teletype add config
$ teletype add create

This will add

create.rb
and
config.rb
commands to the CLI client:
▾ app/
├── ▾ commands/
│   ├── config.rb
│   └── create.rb
├── ▸ templates/
│   ├── ▸ config/
│   └── ▸ create/
├── command.rb
├── cli.rb
└── version.rb

Then you will be able to call the new commands like so:

$ app config
$ app create

The commands require you to specify the actual logic in their

execute
methods.

Please note that command names should be provided as

camelCase
or
snake_case
. For example:
$ teletype add addConfigCommand   # => correct
$ teletype add add_config_command # => correct
$ teletype add add-config-command # => incorrect

2.2.1
--args
flag

You can specify that

teletype
should add a command with a variable number of arguments using the
--args
flag. The
--args
flag accepts space delimited variable names. To specify required argument use a string name, for an optional argument pass
name = nil
enclosed in quote marks and any variable number of arguments needs to be preceded by asterisk:
$ teletype add config --args name           # required argument
$ teletype add config --args "name = nil"   # optional argument
$ teletype add config --args *names         # variadic argument

For more in-depth usage see 2.4 Arguments.

2.2.2
--desc
flag

Every generated command will have a default description 'Command description...', however whilst generating a command you can and should specify a custom description to provide more context with

--desc
flag:
$ teletype add config --desc 'Set and get configuration options'

For more in-depth usage see 2.5 Description.

2.2.3
--force
flag

If you wish to overwrite currently implemented command use

--force
flag:
$ teletype add config --force

2.3 Working with Commands

Running

teletype add config

a new command

config
will be added to
commands
folder creating the following files structure inside the
lib
folder:
▾ app/
├── ▾ commands/
│   └── config.rb
├── ▾ templates/
│   └── ▸ config/
├── cli.rb
├── command.rb
└── version.rb

The

lib/app/cli.rb
file will contain generated command entry which handles the case where the user asks for the
config
command help or invokes the actual command:
module App
  class CLI < Thor
    desc 'config', 'Command description...'
    def config(*)
      if options[:help]
        invoke :help, ['config']
      else
        require_relative 'commands/config'
        App::Commands::Config.new(options).execute
      end
    end
  end
end

And the

lib/app/commands/config.rb
will allow you to specify all the command logic. In the
Config
class which by convention matches the command name, the
execute
method provides a place to implement the command logic:
module App
  module Commands
    class Config < App::Command
      def initialize(options)
        @options = options
      end

  def execute
    # Command logic goes here ...
  end
end

end end

Notice that

Config
inherits from
App::Cmd
class which you have full access to. This class is meant to provide all the convenience methods to lay foundation for any command development. It will lazy load many tty components inside helper methods which you have access to by opening up the
lib/app/command.rb
file.

For example in the

lib/app/command.rb
file, you have access to
prompt
helper for gathering user input:
# The interactive prompt
#
# @see http://www.rubydoc.info/gems/tty-prompt
#
# @api public
def prompt(**options)
  require 'tty-prompt'
  TTY::Prompt.new(options)
end

or a

command
helper for running external commands:
# The external commands runner
#
# @see http://www.rubydoc.info/gems/tty-command
#
# @api public
def command(**options)
  require 'tty-command'
  TTY::Command.new(options)
end

You have full control of the file, so you can use only the tty components that you require. Please bear in mind that all the components are added by default in your

app.gemspec
which you can change to suite your needs and pick only
tty
components that fit your case.

2.4 Arguments

A command may accept a variable number of arguments.

For example, if we wish to have a

config
command that accepts a location of configuration file, then we can run
teletype add
command passing
--args
flag:
$ teletype add config --args file

which will include the required

file
as an argument to the
config
method:
module App
  class CLI < Thor
    desc 'config FILE', 'Set and get configuration options'
    def config(file)
      ...
    end
  end
end

Similarly, if we want to generate command with two required arguments, we run

teletype add
command with
--args
flag that can accept variable names delimited by space character:
$ teletype add set --args name value

will generate the following:

module App
  class CLI < Thor
    desc 'set NAME VALUE', 'Set configuration option'
    def set(name, value)
      ...
    end
  end
end

If we want to have a command that has an optional argument, for example, the

file
argument is an optional argument in the
config
command, then you need to enclose
--args
argument in parentheses:
$ teletype add config --args 'file = nil'

In well behaved command line application, any optional argument in a command will be enclosed in square brackets:

module App
  class CLI < Thor
    desc 'config [FILE]', 'Set and get configuration options'
    def config(file = nil)
      ...
    end
  end
end

If you intend for your command to accept any number of arguments, you need to prefix such argument with an asterisk. For example, if we wish to accept many configuration names:

$ teletype add get --args *names

which will append

...
to the argument description:
module App
  class CLI < Thor
    desc 'get NAMES...', 'Get configuration options'
    def get(*names)
      ...
    end
  end
end

You can mix and match all the above styles of arguments definitions:

$ teletype add config --args file *names

2.5 Description

Use the

desc
method call to describe your command when displayed in terminal. There are two arguments to this method. First, specifies the command name and the actual positional arguments it will accept. The second argument is an actual text description of what the command does.

For example, given the command

config
generated in add command section, we can add description like so:
module App
  class CLI < Thor
    desc 'config [FILE]', 'Set and get configuration options'
    def config(file = nil)
      ...
    end
  end
end

Running

app
executable will include the new description:
Commands:
  app config [FILE]  # Set and get configuration options

To provide long form description of your command use

long_desc
method.
module App
  class CLI < Thor
    desc 'config [FILE]', 'Set and get configuration options'
    long_desc <

Running

app config --help
will produce the following output:
Usage:
  app config

You can query/set/replace/unset options with this command.

The name is an optional key separated by a dot, and the value will be escaped.

This command will fail with non-zero status upon error.

2.6 Options and Flags

Flags and options allow to customize how particular command is invoked and provide additional configuration.

To specify individual flag or option use

method_option
before the command method. All the flags and options can be accessed inside method body via the
options
hash.

Available metadata for an option are:

  • :aliases
    - A list of aliases for this option.
  • :banner
    — A description of the value if the option accepts one.
  • :default
    - The default value of this option if it is not provided.
  • :lazy_default
    — A default that is only passed if the cli option is passed without a value.
  • :desc
    - The short description of the option, printed out in the usage description.
  • :required
    — Indicates that an option is required.
  • :type
    -
    :string
    ,
    :hash
    ,
    :array
    ,
    :numeric
    ,
    :boolean
  • :enum
    — A list of allowed values for this option.

The values for

:type
option are:
  • :boolean
    is parsed as
    --option
  • :string
    is parsed as
    --option=VALUE
    or
    --option VALUE
  • :numeric
    is parsed as
    --option=N
    or
    --option N
  • :array
    is parsed as
    --option=one two three
    or
    --option one two three
  • :hash
    is parsed as
    --option=name:string age:integer

For example, you wish to add an option that allows you to add a new line to a configuration file for a given key with a value thus being able to run

app config --add name value
. To do this, you would need to specify
:array
type for accepting more than one value and
:banner
to provide meaningful description of values:
method_option :add, type: :array, banner: "name value", desc: "Adds a new line the config file. "

The above option would be included in the

config
method like so:
module App
  class CLI < Thor
    desc 'config []', 'Set and get configuration options'
    method_option :add, type: :array, banner: "name value",
                        desc: "Adds a new line the config file. "
    def config(*)
      ...
    end
  end
end

Running

app help config
will output new option:
Usage:
  app config []

Options: [--add=name value] # Adds a new line the config file.

You can also specify an option as a flag without an associated value. Let us assume you want to be able to open a configuration file in your system editor when running

app config --edit
or
app config -e
. This can be achieved by adding the following option:
method_option :edit, type: :boolean, aliases: ['-e'],
                     desc: "Opens an editor to modify the specified config file."

And adding it to the

config
method:
module App
  class CLI < Thor
    desc 'config []', 'Set and get configuration options'
    method_option :edit, type: :boolean, aliases: ['-e'],
                         desc: "Opens an editor to modify the specified config file."
    def config(*)
      ...
    end
  end
end

Next, running

app help config
will produce:
Usage:
  app config []

Options: [--add=name value] # Adds a new line the config file. -e, [--edit], [--no-edit] # Opens an editor to modify the specified config file.

You can use

method_options
as a shorthand for specifying multiple options at once.
method_options %w(list -l) => :boolean, :system => :boolean, :local => :boolean

Once all the command options and flags have been setup, you can access them via

options
hash in command file
lib/app/commands/config.rb
:
module App
  module Commands
    class Config < App::Command
      def initialize(options)
        @options = options
      end

  def execute
    if options[:edit]
      editor.open('path/to/config/file')
    end
  end
end

end end

2.7 Global Flags

You can specify an option or a flag that is applicable to all commands and subcommands within a given class by using the

class_option
method. This method takes exactly the same parameters as
method_option
for an individual command. The
options
hash in a given command will always include a global level flag information.

For example, if you want a global flag

debug
that is visible to all commands in your tool then you need to add it to your
CLI
class like so:
module App
  class CLI < Thor
    class_option :debug, type: :boolean, default: false, desc: 'Run in debug mode'

...

end end

2.8. Working with Subcommands

If your tool grows in complexity you may want to add more refined behaviour for each individual command, a subcommand is a great choice to accomplish this. For example,

git
utility and its
git remote
command have various subcommands
add
,
rename
,
remove
,
set-url
,
prune
and so on that themselves accept many options and arguments.

The

teletype
executable allows you to easily create new subcommands by issuing the same
add
command that is also used for generating commands. The only difference is that you need to provide a command name together with a subcommand name. For example, let's say we want the
config
with a
set
subcommand with a description and two positional arguments
name
and
value
:
$ teletype add config set --desc 'Set configuration option' --args name value

This will add

set.rb
command to the
commands/config
folder:
▾ app/
├── ▾ commands/
│   ├── ▾ config/
│   │   └── set.rb
│   └── config.rb
├── ▾ templates/
│   └── ▾ config/
│       └── ▸ set/
├── cli.rb
├── command.rb
└── version.rb

The

lib/app/cli.rb
will contain code that registers config namespace with our
CLI
root application:
module App
  class CLI < Thor
    require_relative 'commands/config'
    register App::Commands::Config, 'config', 'config [SUBCOMMAND]', 'Set configuration option'
  end
end

The

lib/app/commands/config.rb
will contain code that handles dispatching subcommands to the
Config
instance:
# frozen_string_literal: true

require 'thor'

module App module Commands class Config < Thor

  namespace :config

  desc 'set NAME VALUE', 'Set configuration option'
  def set(name, value)
    if options[:help]
      invoke :help, ['set']
    else
      require_relative 'config/set'
      App::Commands::Config::Set.new(name, value, options).execute
    end
  end
end

end end

And finally, the

lib/app/commands/config/set.rb
will contain the actual
set
command implementation:
# frozen_string_literal: true

require_relative '../../command'

module App module Commands class Config class Set < App::Command def initialize(name, value, options) @name = name @value = value @options = options end

    def execute
      # Command logic goes here ...
    end
  end
end

end end

You can now run your command in terminal:

bundle exec app config set debug true

Note that it is not possible to add subcommands to an existing command. Attempting to do so will currently cause

teletype
to crash. The reason why it is not possible to add subcommands to existing commands is that it is impossible for
tty
to distinguish between normal arguments to a command, and subcommands for that command. However, you may very well add multiple subcommands one after another.

3. Components

The TTY allows you to mix & match any components you need to get your job done. The command line applications generated with

teletype
executable references all of the below components.

| Component | Description | API docs | | ------------ | ----------- | -------- | | pastel | Terminal strings styling with intuitive and clean API. | docs | | tty-box | Draw various frames and boxes in your terminal. | docs | | tty-color | Terminal color capabilities detection. | docs | | tty-command | Execute shell commands with pretty logging and capture stdout, stderr and exit status. | docs | | tty-config | Define, read and write any Ruby app configurations with a penchant for terminal clients. | docs | | tty-cursor | Move terminal cursor around. | docs | | tty-editor | Open a file or text in the user preferred editor. | docs | | tty-file | File manipulation utility methods. | docs | | tty-font | Write text in large stylized characters using a variety of terminal fonts. | docs | | tty-link | Hyperlinks in your terminal. | docs | | tty-logger | A readable and structured logging for the terminal. | docs | | tty-markdown | Convert a markdown document or text into a terminal friendly output. | docs | | tty-option | Parser for command line arguments, keywords and options. | docs | | tty-pager | Terminal output paging in a cross-platform way. | docs | | tty-pie | Draw pie charts in your terminal window. | docs | | tty-platform | Detecting different operating systems. | docs | | tty-progressbar | A flexible progress bars drawing in terminal emulators. | docs | | tty-prompt | A beautiful and powerful interactive command line prompt. | docs | | tty-reader | A set of methods for processing keyboard input in character, line and multiline modes. | docs | | tty-screen | Terminal screen properties detection. | docs | tty-spinner | A terminal spinner for tasks with non-deterministic time.| docs | | tty-table | A flexible and intuitive table output generator. | docs | | tty-tree | Print directory or structured data in a tree like format. | docs | | tty-which | Platform independent implementation of Unix which command. | docs |

4. Contributing

You can contribute by posting

feature requests
, evaluating the APIs or simply by hacking on TTY components:
  1. Fork it
  2. Create your feature branch (
    git checkout -b my-new-feature
    )
  3. Commit your changes (
    git commit -am 'Add some feature'
    )
  4. Push to the branch (
    git push origin my-new-feature
    )
  5. Create new Pull Request

This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

This project uses EditorConfig to maintain consistent tabbing and file formats. Consider installing the plugin for your editor to help maintain proper code formatting.

Copyright

Copyright (c) 2012 Piotr Murach. See LICENSE.txt for further details.

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