Ruby/ProgressBar: A Text Progress Bar Library for Ruby

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The ultimate text progress bar library for Ruby! It'll SMASH YOU OVER THE HEAD with a PURE RUSH of progress bar excitement!

Don't miss out on what all the kids are talking about! If you want everyone to know that your gem or app can survive in the cage then YOU WANT RUBY-PROGRESSBAR!

The Cage

Supported Rubies

  • MRI Ruby 1.8.7
  • MRI Ruby 1.9.2
  • MRI Ruby 1.9.3
  • MRI Ruby 2.0
  • MRI Ruby 2.1
  • JRuby (in 1.8 compat mode)
  • JRuby (in 1.9 compat mode)

It's Better Than The Other 186,312 Progress Bar Libraries Because...

  • Full test suite Code Climate
  • ZERO dependencies
  • Used by tons of other open source projects (which means we find out about bugs quickly)
  • It's pretty freakin' sweet
  • We have a road map of new features to make it even better
  • And most importantly... our awesome contributors



gem install ruby-progressbar

Then in your script:

require 'ruby-progressbar'

or in your Gemfile

gem 'ruby-progressbar'

or from IRB

irb -r 'ruby-progressbar'

Basic Usage


It's simple to get started:


Creates a basic progress bar beginning at 0, a maximum capacity of 100 and tells it to start.

Progress: |                                                                       |

Marking Progress

Every call to #increment will advance the bar by 1. Therefore:

50.times { progressbar.increment }

Would output an advancing line which would end up here:

Progress: |===================================                                    |

Advanced Usage


If you would like to customize your prompt, you can pass options when you call .create.

ProgressBar.create(:title => "Items", :starting_at => 20, :total => 200)

This will output:

Items: |=======                                                                |

The following are the list of options you can use:

  • :title - (Defaults to Progress) - The title of the progress bar.
  • :total - (Defaults to 100) The total number of the items that can be completed.
  • :starting_at - (Defaults to 0) The number of items that should be considered completed when the bar first starts. This is also the default number that the bar will be set to if #reset is called.
  • :progress_mark - (Defaults to =) The mark which indicates the amount of progress that has been made.
  • :remainder_mark - (Defaults to ) The mark which indicates the remaining amount of progress to be made.
  • :format - (Defaults to %t: |%B|) The format string which determines how the bar is displayed. See Formatting below.
  • :length - (Defaults to full width if possible, otherwise 80) The preferred width of the entire progress bar including any format options.
  • :output - (Defaults to STDOUT) All output will be sent to this object. Can be any object which responds to .print .flush .tty? .puts.
  • :smoothing - (Defaults to 0.1) See Smoothing Out Estimated Time Jitters below.
  • :throttle_rate - (Defaults to 0.01) See Throttling below.
  • :unknown_progress_animation_steps - (Defaults to ['=---', '-=--', '--=-', '---=']) See Unknown Progress The graphical elements used to cycle when progress is changed but the total amount of items being processed is unknown.

Changing Progress

  • #increment: Will advance the bar's progress by 1 unit. This is the main way of progressing the bar.
  • #decrement: Will retract the bar's progress by 1 unit.
  • #progress +=: Will allow you to increment by a relative amount.
  • #progress -=: Will allow you to decrement by a relative amount.
  • #progress=: Will set the bar's progress to whatever value you would like. Note: This will likely mess up your estimated time if you're using it.
  • #total=: Will change the total number of items being processed by the bar. This can be anything (even nil) but cannot be less than the amount of progress already accumulated by the bar.


The bar can be stopped in four ways:

  • #finish: Will stop the bar by completing it immediately. The current position will be advanced to the total.
  • #stop: Will stop the bar by immediately cancelling it. The current position will remain where it is.
  • #pause: Will stop the bar like #stop but will allow it to be restarted from where it previously left off by calling #resume. Note: Elapsed Time and Estimated Time will stop being affected while the bar is paused.
  • #reset: Will stop the bar by resetting all information. The current position of the bar will be reset to where it began when it was created. (eg if you passed :starting_at => 5 when you created the bar, it would reset to 5 and not 0)


  • See #finish above.

By default, the bar will be finished automatically if the current value ever becomes equal to the total. If you do not want the bar to autofinish, pass :autofinish => false when creating your bar.

progressbar = ProgressBar.create(:starting_at => 9, :total => 10)

progressbar.finished? # => true
progressbar = ProgressBar.create(:starting_at => 9, :total => 10, :autofinish => false)

progressbar.finished? # => false


  • If you need to redisplay the progress bar to give your users a "real-time" feel, you can call #refresh. #refresh will not affect the current position but will update the elapsed and estimated timers.

Unknown Progress

Sometimes when processing work, you don't know exactly how many items you will need to process. This might be because you're downloading a chunked file or because you're processing a set of jobs that hasn't been fully loaded yet.

In times like these, you can set total to nil and continue to increment the bar as usual. The bar will display an 'unknown' animation which will change every time you increment. This will give the appearance (by default) that the bar is processing work even though there is no "progress".

progressbar = ProgressBar.create(:starting_at => 20, :total => nil)

Will output:

Progress: |=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---|



once more will output:

Progress: |-=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=--|

ad infinitum.

At whatever point you discover the total that you will be processing, you can call: = 100

And the bar will magically transform into its typical state:

Progress: |========                                                            |


While using the progress bar, you may wish to log some output for the user. If you attempt to do this using a standard puts statement, you'll find that the text will overwrite the bar. For example if you were to puts "hello" after progress has already begun, you may get something like this:

helloess: |=======                                                             |
Progress: |========                                                            |

This happens because the ruby-progressbar has to keep redrawing itself every time you change the progress. It's a limitation of terminal output. Using puts messes that up because puts adds a newline which moves the cursor to the next line, then when ruby-progressbar updates, it does so on the following line.

To circumvent this, use #log instead.

progressbar = ProgressBar.create
progressbar.progress = 20
progressbar.log 'hello'
Progress: |=============                                                       |

#log will automatically clear the bar, print your desired text and then redraw the bar on the following line. Notice that we did not get a bar above the logged output. If you consistently use #log, you should only ever see one bar on the screen at any time.


The format of the progress bar is extremely easy to customize. When you create the progress bar and pass the :format option, that string will be used to determine what the bar looks like.

The flags you can use in the format string are as follows:

  • %t: Title
  • %a: Elapsed (absolute) time
  • %e: Estimated time (will fall back to ETA: ??:??:?? when it exceeds 99:00:00)
  • %E: Estimated time (will fall back to ETA: > 4 Days when it exceeds 99:00:00)
  • %f: Force estimated time to be displayed even if it exceeds 99:00:00
  • %p: Percentage complete represented as a whole number (eg: 82)
  • %P: Percentage complete represented as a decimal number (eg: 82.33)
  • %j: Percentage complete right-justified to 3 places (eg: 82)
  • %J: Percentage complete right-justified to 6 places (eg: 82.33)
  • %c: Number of items currently completed
  • %C: Total number of items to be completed
  • %B: The full progress bar including 'incomplete' space (eg: ==========)
  • %b: Progress bar only (eg: ==========)
  • %w: Bar With Integrated Percentage (eg: ==== 75 ====)
  • %r: Rate of Progress as a whole number (eg: 13)
  • %R: Rate of Progress as a decimal number (eg: 13.67)
  • %i: Display the incomplete space of the bar (this string will only contain whitespace eg: )
  • %%: A literal percent sign %

All values have an absolute length with the exception of the bar flags (eg %B, %b, etc) which will occupy any leftover space. You can use as many bar flags as you'd like, but if you do weird things, weird things will happen; so be wary.


If you would like a bar with the elapsed time on the left and the percentage complete followed by the title on the right, you'd do this:

ProgressBar.create(:format => '%a %B %p%% %t')

Which will output something like this:

Time: --:--:--                                                   0% Progress

Hard to see where the bar is? Just add your own end caps, whatever you'd like. Like so:

ProgressBar.create(:format => '%a <%B> %p%% %t')


Time: --:--:-- <                                               > 0% Progress

Want to put an end cap on your bar? Nothing special, just use the bar flag %b combined with the incomplete space flag %i like so:

ProgressBar.create(:format => '%a |%b>>%i| %p%% %t', :starting_at => 10)


Time: --:--:-- |====>>                                        | 10% Progress

Notice that the absolute length doesn't get any longer, the bar just shrinks to fill the remaining space.

Want to play a game of PAC-MAN while you wait for your progress?

ProgressBar.create( :format         => '%a %bᗧ%i %p%% %t',
                    :progress_mark  => ' ',
                    :remainder_mark => '',
                    :starting_at    => 10)

Becomes PAC-MAN!

Time: --:--:--       ᗧ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ 10% Progress

Overriding the Length

By default, the progress bar will try to be as smart as possible about how wide it can be. Under most Unix systems, it should be as wide as the terminal will allow while still fitting on one line. If you wish to override this behavior, you can pass in the :length option when creating the bar:

ProgressBar.create(:length => 40)

If you don't have access to the code calling the progress bar itself (say if you're using a gem like Fuubar), you can set the RUBY_PROGRESS_BAR_LENGTH environment variable and it will override any other setting.

Note: If the terminal width is less than 20 characters or ruby-progressbar is being used on a non-*nix system, the bar will default to an 80 character width.

Realtime Customization

The following items can be set at any time. Changes cause an immediate bar refresh so no other action is needed:

  • #progress_mark=: Sets the string used to represent progress along the bar.
  • #remainder_mark=: Sets the string used to represent the empty part of the bar.
  • #title=: Sets the string used to represent the items the bar is tracking (or I guess whatever else you want it to be).
  • #format(format_string): If you need to adjust the format that the bar uses when rendering itself, just pass in a string in the same format as describe above.

Rate Scaling

By default the rate shown on the progress bar is shown as the number of items processed per second. Often times, you won't want to display the literal number of items, but rather scale it in some way. For example, if you're displaying the progress of a file being transferred, and you are representing the bar as the number of bytes in the file, by default the %r formatter will show the number of bytes per second.

If instead of the bytes per second you wanted to show the user the number of kilobytes per second, you can do that like so:

ProgressBar.create(:format     => '%a %B %p%% %r KB/sec',
                   :rate_scale => lambda { |rate| rate / 1024 })

Now, when the bar is displayed it will look something like so:

Time: --:--:-- ===============                                40% - 102 KB/sec

In The Weeds

This is some stuff that makes ruby-progressbar extra awesome, but for the most part it "Just Works" and you won't have to even know it's there, but if you're curious like us, here it is.

Times... They Are A Changin'

Smoothing Out Estimated Time Jitters

Sometimes when you're tracking progress, you might have some items which take significantly longer than others to complete. When this is the case, the ETA gauge can vary wildly from increment to increment.


Thanks to @L2G and 'the maths' you can pass the :smoothing option when creating a new bar. Your progress bar will then use an exponentially smoothed average rather than a linear one. A value of 0.0 means no smoothing and is equivalent to the classic behavior. A value of 1.0 is the maximum amount of smoothing. Any values between those two are valid. The default value is 0.1.

ProgressBar.create(:smoothing => 0.6)

Time Mocking Support

When mocking time, the concept of when now is becomes distorted. You can imagine that because ruby-progressbar tracks elapsed and estimated times, if it used the mocked version of now the results would be very undesirable. But, if you use one of our supported Ruby time mocking libraries, your elapsed and estimated times will always appear correctly. Currently supported are:


When reporting progress of large amounts of very fast operations, whose duration is comparable to the output time of a progress bar, it becomes desirable to throttle output to the console and only perform it once in a set period. ProgressBar supports throttling if given :throttle_rate option:

ProgressBar.create(:throttle_rate => 0.1)

The above progress bar will output at most 10 times a second.

The default throttling rate is 100 times per second (or 0.01)

Custom Unknown Progress Animations

Following up on unknown progress, you may wish to update the unknown progress animation to suit your specific needs. This can be easily done by passing in the :unknown_progress_animation_steps option.

This item should be an array of strings that represent each step of the animation. The specific step used for a given progress is determined by the current progress of the bar. For example:

progressbar = ProgressBar.create(:unknown_progress_animation_steps => ['==>', '>==', '=>='])

Would use element 0 ('==>') for a progress of 1, 4, 7, 10, etc. It would use element 3 for a progress of 3, 6, 9, 12, etc.

You can have an array of as many elements as you'd like and they will be used in the same manner. For example if you have an array of 50 animation steps, element 0 would only be used for every 50th progress (eg: 1, 51, 101, etc).

Whatever element is chosen is repeated along the entire 'incomplete' portion of the bar.

Non-TTY Output

Normally, when the progress bar is updated, the entire previous bar is 'overwritten' with the updated information. However when the bar is being output on a non-TTY enabled output stream (such as a file or pipe), that standard behavior of outputting the progress bar will not work. This is mainly due to the fact that we can't easily go back and replace the content that the bar had previously written.

To try to solve this problem, ruby-progressbar, when it determines that it is being used on a non-TTY device, will override any format which was set in the initializer to something which more closely resembles this:

Progress: |=============

Notice that there are no dynamically updating segments like counters or ETA. Dynamic segments are incompatible with non-TTY devices. This is because dynamic segments need to be updated on each refresh of the bar, which is impossible in non-TTY mode.

Also notice that there is no end cap on the righthand side of the bar. Again, we cannot output something which is past the point at which we next need to output text. If we added an end cap, that would mean that any additional progress text would be placed after the end cap. Definitely not what we want.

So how does it work?

First we output the title and the first end cap:

Progress: |

Next, every time we increment the bar, we check whether the progress bar has grown. If it has, we only output the additional portion of the bar to the output.

For example, given the previous title output, if we increment the bar once, we would get:

Progress: |=

But in this case, only one = was output. Not the entire Progress: |=.

However when the bar is completed:

Progress: |====================================================================|

The end cap can now be added (since there is no more progress to be displayed).


If you have problems, please create a Github issue.



ruby-progressbar is maintained by The Kompanee, Ltd.

The names and logos for The Kompanee are trademarks of The Kompanee, Ltd.



Thanks to @nex3 for giving us contributor access to the initial repo. Thanks to Hiroyuki Iwatsuki for giving us access to the gem on to allow us to push our new versions.

And a special thanks to Satoru Takabayashi who was the original author of the progressbar gem and who inspired us to do this rewrite.


ruby-progressbar 1.0 is Copyright © 2011-2014 The Kompanee. It is free software, and may be redistributed under the terms specified in the LICENSE file. ruby-progressbar 0.9.0 is Copyright © 2008 Satoru Takabayashi