Toolkit for developing sleek command line apps.
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.
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.
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
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
teletypeexecutable:
$ 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.
newcommand
Running
teletype new [app-name]will bootstrap an entire project file structure based on the bundler
gemcommand setup enhanced by additional files and folders related to command application development.
For example, to create a new command line application called
appdo:
$ 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
appfolder 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.rbprovides 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) => :version
end end
This is where all your application commands and subcommands will be defined.
Teletype uses
Thoras an option parsing library by directly inheriting from it.
And also by convention the
startmethod is used to parse the command line arguments inside the
appexecutable:
App::CLI.start
Run the new command with
--helpor
-hflag to see all available options:
$ teletype new --help $ teletype new -h
Execute
teletypeto see all available commands.
--author,
-aflag
The
teletypegenerator can inject name into documentation for you:
$ teletype new app --author 'Piotr Murach'
--extflag
To specify that
teletypeshould create a binary executable (as
exe/GEM_NAME) in the generated project use the
--extflag. This binary will also be included in the
GEM_NAME.gemspecmanifest. This is disabled by default, to enable do:
$ teletype new app --ext
--license,
-lflag
The
teletypegenerator comes prepackaged with most popular open source licenses:
agplv3,
apache,
bsd2,
bsd3,
gplv2,
gplv3,
lgplv3,
mit,
mplv2,
custom. By default the
mitlicense is used. To change that do:
$ teletype new app --license bsd3
--test,
-tflag
The
teletypecomes configured to work with
rspecand
minitestframeworks which are the only two acceptable values. The
GEM_NAME.gemspecwill be configured and appropriate testing directory setup. By default the
RSpecframework is used.
$ teletype new app --test=minitest $ teletype new app -t=minitest
addcommand
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.rband
config.rbcommands 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
executemethods.
Please note that command names should be provided as
camelCaseor
snake_case. For example:
$ teletype add addConfigCommand # => correct $ teletype add add_config_command # => correct $ teletype add add-config-command # => incorrect
--argsflag
You can specify that
teletypeshould add a command with a variable number of arguments using the
--argsflag. The
--argsflag accepts space delimited variable names. To specify required argument use a string name, for an optional argument pass
name = nilenclosed 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.
--descflag
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
--descflag:
$ teletype add config --desc 'Set and get configuration options'
For more in-depth usage see 2.5 Description.
--forceflag
If you wish to overwrite currently implemented command use
--forceflag:
$ teletype add config --force
Running
teletype add config
a new command
configwill be added to
commandsfolder creating the following files structure inside the
libfolder:
▾ app/ ├── ▾ commands/ │ └── config.rb ├── ▾ templates/ │ └── ▸ config/ ├── cli.rb ├── command.rb └── version.rb
The
lib/app/cli.rbfile will contain generated command entry which handles the case where the user asks for the
configcommand 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.rbwill allow you to specify all the command logic. In the
Configclass which by convention matches the command name, the
executemethod provides a place to implement the command logic:
module App module Commands class Config < App::Command def initialize(options) @options = options enddef execute # Command logic goes here ... end end
end end
Notice that
Configinherits from
App::Cmdclass 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.rbfile.
For example in the
lib/app/command.rbfile, you have access to
prompthelper 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
commandhelper 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.gemspecwhich you can change to suite your needs and pick only
ttycomponents that fit your case.
A command may accept a variable number of arguments.
For example, if we wish to have a
configcommand that accepts a location of configuration file, then we can run
teletype addcommand passing
--argsflag:
$ teletype add config --args file
which will include the required
fileas an argument to the
configmethod:
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 addcommand with
--argsflag 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
fileargument is an optional argument in the
configcommand, then you need to enclose
--argsargument 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
Use the
descmethod 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
configgenerated 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
appexecutable will include the new description:
Commands: app config [FILE] # Set and get configuration options
To provide long form description of your command use
long_descmethod.
module App class CLI < Thor desc 'config [FILE]', 'Set and get configuration options' long_desc <Running
app config --helpwill produce the following output:Usage: app configYou 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_optionbefore the command method. All the flags and options can be accessed inside method body via theoptionshash.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
:typeoption are:
:booleanis parsed as
--option
:stringis parsed as
--option=VALUEor
--option VALUE
:numericis parsed as
--option=Nor
--option N
:arrayis parsed as
--option=one two threeor
--option one two three
:hashis 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
:arraytype for accepting more than one value and
:bannerto 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
configmethod 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 configwill 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 --editor
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
configmethod:
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 configwill 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_optionsas 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
optionshash in command file
lib/app/commands/config.rb:
module App module Commands class Config < App::Command def initialize(options) @options = options enddef execute if options[:edit] editor.open('path/to/config/file') end end end
end end
You can specify an option or a flag that is applicable to all commands and subcommands within a given class by using the
class_optionmethod. This method takes exactly the same parameters as
method_optionfor an individual command. The
optionshash in a given command will always include a global level flag information.
For example, if you want a global flag
debugthat is visible to all commands in your tool then you need to add it to your
CLIclass like so:
module App class CLI < Thor class_option :debug, type: :boolean, default: false, desc: 'Run in debug mode'...
end end
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,
gitutility and its
git remotecommand have various subcommands
add,
rename,
remove,
set-url,
pruneand so on that themselves accept many options and arguments.
The
teletypeexecutable allows you to easily create new subcommands by issuing the same
addcommand 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
configwith a
setsubcommand with a description and two positional arguments
nameand
value:
$ teletype add config set --desc 'Set configuration option' --args name value
This will add
set.rbcommand to the
commands/configfolder:
▾ app/ ├── ▾ commands/ │ ├── ▾ config/ │ │ └── set.rb │ └── config.rb ├── ▾ templates/ │ └── ▾ config/ │ └── ▸ set/ ├── cli.rb ├── command.rb └── version.rb
The
lib/app/cli.rbwill contain code that registers config namespace with our
CLIroot 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.rbwill contain code that handles dispatching subcommands to the
Configinstance:
# frozen_string_literal: truerequire '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.rbwill contain the actual
setcommand implementation:
# frozen_string_literal: truerequire_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
teletypeto crash. The reason why it is not possible to add subcommands to existing commands is that it is impossible for
ttyto distinguish between normal arguments to a command, and subcommands for that command. However, you may very well add multiple subcommands one after another.
The TTY allows you to mix & match any components you need to get your job done. The command line applications generated with
teletypeexecutable 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 |
You can contribute by posting
feature requests, evaluating the APIs or simply by hacking on TTY components:
git checkout -b my-new-feature)
git commit -am 'Add some feature')
git push origin my-new-feature)
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 (c) 2012 Piotr Murach. See LICENSE.txt for further details.