TTY::ProgressBar Gitter

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A flexible progress bars drawing in terminal emulators.

TTY::ProgressBar provides independent progress bars component for TTY toolkit.


  • Fully configurable
  • Extremly flexible progress display formatting
  • Ability to define your custom format tokens
  • Works on all ECMA-48 compatible terminals


Add this line to your application's Gemfile:

gem 'tty-progressbar'

And then execute:

$ bundle

Or install it yourself as:

$ gem install tty-progressbar


1. Usage

TTY::ProgressBar requires only format string and total number of steps to completion. Once initialized, use advance method to indicated the progress like so:

bar ="downloading [:bar]", total: 30)
30.times do

This would produce animation in your terminal:

downloading [=======================       ]

1.1 advance

Once you have TTY::ProgressBar instance, you can progress the display by calling advance method. By default it will increase by 1 but you can pass any number of steps, for instance, when used to advance number of bytes of downloaded file.


You can also pass negative steps if you wish to backtrack the progress:


Note: If a progress bar has already finished then negative steps will not set it back to desired value.

1.2 current=

TTY::ProgressBar allows you to set progress to a given value by calling current= method.

bar.current = 50

Note: If a progress bar has already finished then negative steps will not set it back to desired value.

1.3 ratio=

In order to update overall completion of a progress bar as an exact percentage use the ratio= method. The method accepts values between 0 and 1 inclusive. For example, a ratio of 0.5 will attempt to set the progress bar halfway:

bar.ratio = 0.5

1.4 width=

You can set how many terminal columns will the :bar actually span excluding any other tokens and/or text. For example if you need the bar to be always 20 columns wwide do:

bar.width = 20

or with configuration options:

bar ="[:bar]", width: 20)

1.5 start

By default the timer for internal time esitamation is started automatically when the advance method is called. However, if you require control on when the progression timer is started use start call:

bar.start  # => sets timer and draws initial progress bar

1.6 finish

In order to immediately stop and finish the progress call finish. This will finish drawing the progress and return to new line.


1.7 complete?

During progresion you can check if bar is finished or not by calling complete?.

bar.complete? # => false

1.8 reset

In order to reset currently running or finished progress bar to its original configuration and initial position use reset like so:


1.9 resize

If you wish for a progress bar to change it's current width, you can use resize by passing in a new desired length. However, if you don't provide any width the resize will use terminal current width as its base for scaling.

bar.resize      # => determine terminal width and scale accordingly
bar.resize(50)  # => will resize bar proportionately from this point onwards

To handle automatic resizing you can trap :WINCH signal:

trap(:WINCH) { bar.resize }

2. Configuration

There are number of configuration options that can be provided:

  • total total number of steps to completion
  • width of the bars display in terminal columns excluding formatting options. Defaults to total steps
  • complete completion character by default =
  • incomplete incomplete character by default single space
  • output the output stream defaulting to stderr
  • frequency used to throttle the output, by default 0 (see Frequency)
  • interval used to measure the speed, by default 1 sec (see Interval)
  • hide_cursor to hide display cursor defaulting to false
  • clear to clear the finished bar defaulting to false

All the above options can be passed in as hash options or block parameters: "[:bar]" do |config| = 30
  config.frequency = 10
  config.clear = true

2.1 Frequency

Each time the advance is called it causes the progress bar to repaint. In cases when there is a huge number of updates per second, you may need to limit the rendering process by using the frequency option.

The frequency option accepts integer representing number of Hz units, for instance, frequency of 2 will mean that the progress will be updated maximum 2 times per second."[:bar]", total: 30, frequency: 10) # 10 Hz

2.2 Interval

For every call of advance method the ProgressBar takes a sample for speed measurement. By default the samples are grouped per second but you can change that by passing the interval option.

The interval option is an integer that represents the number of seconds, for example, interval of 60 would mean that speed is measured per 1 minute.":rate/minute", total: 100, interval: 60) # 1 minute":rate/hour", total: 100, interval: 3600) # 1 hour

3. Formatting

Every TTY::ProgressBar instance requires a format string, which apart from regular characters accepts special tokens to display dynamic information. For instance, a format to measure download progress could be:

"downloading [:bar] :elapsed :percent"

3.1 Tokens

These are the tokens that are currently supported:

  • :bar the progress bar
  • :current the current progress number
  • :current_byte the current progress in bytes
  • :total the total progress number
  • :total_byte the total progress in bytes
  • :percent the completion percentage
  • :elapsed the elapsed time in seconds
  • :eta the esitmated time to completion in seconds
  • :rate the current rate of progression per second
  • :byte_rate the current rate of pregression in bytes per second
  • :mean_rate the averaged rate of progression per second
  • :mean_byte the averaged rate of progression in bytes per second

3.2 Custom Formatters

If the provided tokens do not meet your needs, you can write your own formatter and instrument formatting pipeline to use a formatter you prefer. This option is preferred if you are going to rely on progress bar internal data such as rate, current etc. which will all be available on the passed in progress bar instance.

For example, begin by creating custom formatter called TimeFormatter that will dynamicly update :time token in format string. The methods that you need to specify are initialize, matches? and format like follows:

class TimeFormatter
  def initialize(progress)
    @progress = progress # current progress bar instance

  def matches?(value)  # specify condition to match for in display string
    value.to_s =~ /:time/

  def format(value)  # specify how display string is formatted
    transformed = ( - @progress.start_at).to_s
    value.gsub(/:time/, transformed)   # => :time token replacement

Notice that you have access to all the configuration options inside the formatter by simply invoking them on the @progress instance.

Create TTY::ProgressBar instance with new token:

bar =":time", total: 30)

Then add TimeFormatter to the pipeline like so:

bar.use TimeFormatter

and then invoke progression:


3.3 Custom Tokens

You can define custom tokens by passing pairs name: value to advance method in order to dynamically update formatted bar. This option is useful for lightweight content replacement such as titles that doesn't depend on the internal data of progressbar. For example:

bar ="(:current) :title", total: 4)
bar.advance(title: 'Hello Piotr!')
bar.advance(3, title: 'Bye Piotr!')

which outputs:

(1) Hello Piotr!
(4) Bye Piotr!

4. Logging

If you want to print messages out to terminal along with the progress bar use the log method. The messages will appear above the progress bar and will continue scrolling up as more are logged out.


will result in:

downloading [=======================       ]

5. Examples

This section demonstrates some of the possible uses for the TTY::ProgressBar, for more please see examples folder in the source directory.

5.1 Colors

Creating a progress bar that displays in color is as simple as coloring the :complete and :incomplete character options. In order to help with coloring you can use pastel library like so:

require 'pastel'

pastel =
green  = pastel.on_green(" ")
red    = pastel.on_red(" ")

And then pass in the colored strings as options to TTY::ProgressBar:

bar ="|:bar|",
  total: 30,
  complete: green,
  incomplete: red

To see how a progress bar is reported in terminal you can do:

30.times do

5.2 Speed

Commonly a progress bar is utilized to measure download speed per second. This can be done like so:"[:bar] :byte_rate/s") do |config| = 300000
  config.interval = 1     # => 1 sec

This will result in output similar to:

downloading [=======================       ] 4.12MB/s


  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 a new Pull Request


Copyright (c) 2014-2016 Piotr Murach. See LICENSE for further details.