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Toolbox for developing CLI clients in Ruby. This library provides a fluid interface for working with terminals.


Jump-start development of your command line app:

  • Table rendering with an easy-to-use API. [status: In Progress]
  • Terminal output colorization. [status: ✔ ]
  • Terminal output paging. [status: ✔ ]
  • System & command detection utilities. [status: In Progress]
  • Text manipulation(wrapping/truncation) [status: In Progress]
  • Shell user interface. [status: In Progress]
  • File diffs. [status: TODO]
  • Progress bar. [status: TODO]
  • Configuration file management. [status: TODO]
  • Logging [status: In Progress]
  • Plugin ecosystem [status: TODO]
  • Fully tested with major ruby interpreters.
  • No dependencies to allow for easy gem vendoring.


Add this line to your application's Gemfile:

gem 'tty'

And then execute:

$ bundle

Or install it yourself as:

$ gem install tty



To instantiate table pass 2-dimensional array:

table = TTY::Table[['a1', 'a2'], ['b1', 'b2']]
table = [['a1', 'a2'], ['b1', 'b2']]
table = rows: [['a1', 'a2'], ['b1', 'b2']]
table = ['h1', 'h2'], [['a1', 'a2'], ['b1', 'b2']]
table = header: ['h1', 'h2'], rows: [['a1', 'a2'], ['b1', 'b2']]

or cross header with rows inside a hash like so

table = [{'h1' => ['a1', 'a2'], 'h2' => ['b1', 'b2']}]

Table behaves like an Array so <<, each and familiar methods can be used

table << ['a1', 'a2', 'a3']
table << ['b1', 'b2', 'b3']
table << ['a1', 'a2'] << ['b1', 'b2']  # chain rows assignment

table.each { |row| ... }  # iterate over rows
table.each_with_index     # iterate over each element with row and column index
table[i, j]               # return element at row(i) and column(j)
table.row(i) { ... }      # return array for row(i)
table.column(j) { ... }   # return array for column(j)
table.column(name)        # return array for column(name), name of header
table.row_size            # return row size
table.column_size         # return column size
table.size                # return an array of [row_size, column_size]
table.border              # specify border properties

or pass your rows in a block

table =  do |t|
  t << ['a1', 'a2', 'a3']
  t << ['b1', 'b2', 'b3']


Once you have an instance of TTY::Table you can print it out to the stdout by doing:


a1  a2  a3
b1  b2  b3

This will use so called basic renderer with default options.

However, you can include other customization options such as

border         # hash of border properties out of :characters, :style, :separator keys
border_class   # a type of border to use
column_widths  # array of maximum columns widths
column_aligns  # array of cell alignments out of :left, :center and :right, default :left
filter         # a proc object that is applied to every field in a row
indent         # indentation applied to rendered table
multiline      # if true will wrap text at new line or column width,
               # when false will escape special characters
orientation    # either :horizontal or :vertical
padding        # array of integers to set table fields padding
renderer       # enforce display type out of :basic, :color, :unicode, :ascii
resize         # if true will expand/shrink table column sizes to match the width,
               # otherwise if false rotate table vertically
width          # constrain the table total width, otherwise dynamically
               # calculated from content and terminal size


Renderer options may include multiline parameter. The true value will cause the table fields wrap at their natural line breaks or in case when the column widths are set the content will wrap.

table = [ ["First", '1'], ["Multi\nLine\nContent", '2'], ["Third", '3']]
table.render :ascii, multiline: true
# =>
  |First  |1|
  |Multi  |2|
  |Line   | |
  |Content| |
  |Third  |3|

When the false option is specified all the special characters will be escaped and if the column widths are set the content will be truncated like so

table = [ ["First", '1'], ["Multiline\nContent", '2'], ["Third", '3']]
table.render :ascii, multiline: false
# =>
  |First             |1|
  |Third             |3|


To print border around data table you need to specify renderer type out of basic, ascii, unicode. By default basic is used. For instance, to output unicode border:

table = ['header1', 'header2'], [['a1', 'a2'], ['b1', 'b2']
table.render :unicode
# =>
  │a1     │a2     │
  │b1     │b2     │

You can also create your own custom border by subclassing TTY::Table::Border and implementing the def_border method using internal DSL methods like so:

class MyBorder < TTY::Table::Border
  def_border do
    left         '$'
    center       '$'
    right        '$'
    bottom       ' '
    bottom_mid   '*'
    bottom_left  '*'
    bottom_right '*'

Next pass the border class to your table instance render_with method

table = ['header1', 'header2'], [['a1', 'a2'], ['b1', 'b2']
table.render_with MyBorder
# =>
  $a1     $a2     $
  *       *       *

Finally, if you want to introduce slight modifications to the predefined border types, you can use table border helper like so

table = ['header1', 'header2'], [['a1', 'a2'], ['b1', 'b2']
table.render do |renderer|
  renderer.border do
    mid          '='
    mid_mid      ' '
# =>
  header1 header2
  ======= =======
  a1      a2
  b1      b2

In addition to specifying border characters you can force table to render separator line on each row like:

table = ['header1', 'header2'], [['a1', 'a2'], ['b1', 'b2']]
table.render do |renderer|
  renderer.border.separator = :each_row
# =>
  |a1     |a2     |
  |b1     |b2     |

Also to change the display color of your border do:

table.render do |renderer| = :red


All columns are left aligned by default. You can enforce per column alignment by passing column_aligns option like so

rows = [['a1', 'a2'], ['b1', 'b2']
table = rows: rows
table.render column_aligns: [:center, :right]

To align a single column do

table.align_column(1, :right)

If you require a more granular alignment you can align individual fields in a row by passing align option

table = do |t|
  t << ['a1', 'a2', 'a3']
  t << ['b1', {:value => 'b2', :align => :right}, 'b3']
  t << ['c1', 'c2', {:value => 'c3', :align => :center}]


By default padding is not applied. You can add padding to table fields like so

heaer = ['Field', 'Type', 'Null', 'Key', 'Default', 'Extra']
rows  = [['id', 'int(11)', 'YES', 'nil', 'NULL', '']]
table =, rows)
table.render { |renderer| renderer.padding= [0,1,0,1] }
# =>
  | Field | Type    | Null | Key | Default | Extra |
  | id    | int(11) | YES  | nil | NULL    |       |

or you can set specific padding using right, left, top, bottom helpers. However, when adding top or bottom padding a multiline option needs to be set to true to allow for rows to span multiple lines. For example

table.render { |renderer|
  renderer.multiline = true = 1
# =>
  |     |       |    |   |       |     |
  |Field|Type   |Null|Key|Default|Extra|
  |     |       |    |   |       |     |
  |id   |int(11)|YES |nil|NULL   |     |


You can define filters that will modify individual table fields value before they are rendered. A filter can be a callable such as proc. Here's an example that formats

table = ['header1', 'header2'], [['a1', 'a2'], ['b1', 'b2']
table.render do |renderer|
  renderer.filter = do |val, row_index, col_index|
    if col_index == 1 and !(row_index == 0)
# =>
  |a1     |A2     |
  |b1     |B2     |

To color even fields red on green background add filter like so

table.render do |renderer|
  renderer.filter = proc do |val, row_index, col_index|
    col_index % 2 == 1 ? TTY.color.set(val, :red, :on_green) : val


To control table's column sizes pass width, resize options. By default table's natural column widths are calculated from the content. If the total table width does not fit in terminal window then the table is rotated vertically to preserve content.

The resize property will force the table to expand/shrink to match the terminal width or custom width. On its own the width property will not resize table but only enforce table vertical rotation if content overspills.

header = ['h1', 'h2', 'h3']
rows   = [['aaa1', 'aa2', 'aaaaaaa3'], ['b1', 'b2', 'b3']]
table = header, rows
table.render width: 80, resize: true
# =>
  |h1       |h2     |h3          |
  |aaa1     |aa2    |aaaaaaa3    |
  |b1       |b2     |b3          |


To read general terminal properties you can use on of the helpers

term =
term.width              # => 140
term.height             # =>  60
term.color?             # => true or false
term.echo(false) { }    # switch off echo for the block               # page terminal output, on non unix systems falls back to ruby implementation

To colorize your output do

term.color.set 'text...', :bold, :red, :on_green    # => red bold text on green background
term.color.remove 'text...'       # strips off ansi escape sequences
term.color.code :red              # ansi escape code for the supplied color

Available colors are:


To supply background color simply prefix it with on_. For example a green background would be on_green.

To page your output do 'long text...'


Main responsibility is to interact with the prompt and provide convenience methods.

Available methods are

shell =
shell.ask          # print question         # read from stdin
shell.say          # print message to stdout
shell.confirm      # print message(s) in green
shell.warn         # print message(s) in yellow
shell.error        # print message(s) in red
shell.suggest      # print suggestion message based on possible matches
shell.print_table  # print table to stdout

In order to ask question and parse answers:

shell  =
answer = shell.ask("What is your name?").read_string

The library provides small DSL to help with parsing and asking precise questions

argument    # :required or :optional
character   # turn character based input, otherwise line (default: false)
clean       # reset question
default     # default value used if none is provided
echo        # turn echo on and off (default: true)
mask        # mask characters i.e '****' (default: false)
modify      # apply answer modification :upcase, :downcase, :trim, :chomp etc..
range       # specify range '0-9', '0..9', '0...9' or negative '-1..-9'
validate    # regex against which stdin input is checked
valid       # a list of expected valid options

You can chain question methods or configure them inside a block

shell.ask("What is your name?").argument(:required).default('Piotr').validate(/\w+\s\w+/).read_string

shell.ask "What is your name?" do
  argument :required
  default  'Piotr'
  validate /\w+\s\w+/
  valid    ['Piotr', 'Piotrek']
  modify   :capitalize

Reading answers and converting them into required types can be done with custom readers

read_bool       # return true or false for strings such as "Yes", "No"
read_char       # return first character
read_date       # return date type
read_datetime   # return datetime type
read_email      # validate answer against email regex
read_file       # return a File object
read_float      # return decimal or error if cannot convert
read_int        # return integer or error if cannot convert
read_multiple   # return multiple line string
read_password   # return string with echo turned off
read_range      # return range type
read_regex      # return regex expression
read_string     # return string
read_symbol     # return symbol
read_text       # return multiline string

For example, if we wanted to ask a user for a single digit in given range

ask("Provide number in range: 0-9") do
  range '0-9'
  on_error :retry

on the other hand, if we are interested in range answer then

ask("Provide range of numbers?").read_range

To suggest possible matches for the user input use suggest method like so

shell.suggest('sta', ['stage', 'stash', 'commit', 'branch'])# =>

  Did you mean one of these?


TTY::System.unix?        # check if unix platform     # check if windows platform
TTY::System.which(cmd)   # full path to executable if found, nil otherwise
TTY::System.exists?(cmd) # check if command is available
TTY::System.editor       # provides access to system editor

To set preferred editor you can either use shell environment variables such as EDITOR and VISUAL or set the command(s) manually like so


To open a file in your editor of choice do'file path...')


  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


Copyright (c) 2012-2013 Piotr Murach. See LICENSE for further details.