++ed by:

1 PAUSE user

Scott Wiersdorf
and 1 contributors


Term::Twiddle - Twiddles a thingy while-u-wait


  use Term::Twiddle;
  my $spinner = new Term::Twiddle;

  system('tar', '-xvf', 'some_phat_tarfile.tar');

  $spinner->random;  ## makes it appear to really struggle at times!


Always fascinated by the spinner during FreeBSD's loader bootstrap, I wanted to capture it so I could view it any time I wanted to--and I wanted to make other people find that same joy I did. Now, anytime you or your users have to wait for something to finish, instead of twiddling their thumbs, they can watch the computer twiddle its thumbs.

During Twiddling

Once the twiddler/spinner is in motion you need to do something (e.g., unpack a tar file, call some long function, etc.). You can do almost anything in between start and stop as long as there are no sleep calls in there (unless the process has been forked, as in a Perl system call). From Time::HiRes:

    Use of interval timers may interfere with alarm(), sleep(), and
    usleep().  In standard-speak the "interaction is unspecified",
    which means that anything may happen: it may work, it may not.

Try not to do any terminal I/O while the twiddler is going (unless you don't mind dragging the twiddler around with your cursor).

Spinner Methods


Creates a new Twiddle object:

    my $spinner = new Term::Twiddle;

Optionally initializes the Twiddle object:

    ## a moderately paced spinner
    my $spinner = new Term::Twiddle( { rate => 0.075 } );

Starts the twiddler twiddling:


Stops the twiddler:


Creates a new thingy. The argument is a reference to a list of strings to print (usually single characters) so that animation looks good. The default spinner sequence looks like this:

    $spinner->thingy( [ "\\", "|", "/", "-" ] );

an arrow could be done like this: $spinner->thingy( [ "---->", " ----->", " ----->", " ----->", " ----->|", " ---->|", " --->|", " -->|", " ->|", " >|", " |", " "]);

Look at the test.pl file for this package for more fun thingy ideas.


Changes the rate at which the thingy is changing (e.g., spinner is spinning). This is the time to wait between thingy characters (or "frames") in seconds. Fractions of seconds are supported. The default rate is 0.175 seconds.

    $spinner->rate(0.075);  ## faster!

Determines how likely it is for each step in the thingy's motion to change rate of change. That is, each time the thingy advances in its sequence, a random number from 1 to 100 is generated. If probability is set, it is compared to the random number. If the probability is greater than or equal to the randomly generated number, then a new rate of change is randomly computed (between 0 and 0.2 seconds).

In short, if you want the thingy to change rates often, set probability high. Otherwise set it low. If you don't want the rate to change ever, set it to 0 (zero). 0 is the default.

    ## half of all sequence changes will result in a new rate of change

The purpose of this is to create a random rate of change for the thingy, giving the impression that whatever the user is waiting for is certainly doing a lot of work (e.g., as the rate slows, the computer is working harder, as the rate increases, the computer is working very fast. Either way your computer looks good!).


Invokes the probability method with the argument specified. If no argument is specified, 25 is the default value. This is meant as a short-cut for the probability method.


Select an alternate stream to print on. By default, STDOUT is printed to.


Alternative Spinner Methods

Since version 2.70, Term::Twiddle objects support a couple of new spinners that aren't so "plain". 2.70 includes a bounceing ball and a swishing object (that's the best name I could think to call it).

The following methods are used to activate and customize these new spinners.


Use this method to set the type of spinner. The default type (no type) is whatever thingy is set to. Two other currently supported types are bounce, and swish. These may be set in the constructor:

    my $sp = new Term::Twiddle({ type => 'bounce' });

or you can set it with this type method:

    my $sp = new Term::Twiddle;

There is currently no way to add new types without some hacking (it's on the "to do" list).


This method is only used when type is undefined (i.e., a normal spinner). width determines how wide the bounce or swish objects go. width may be set in the constructor:

    my $sp = new Term::Twiddle({ type => 'bounce', width => 60 });

or you can set it with this width method:

    my $sp = new Term::Twiddle({ type => 'swish' });

Determines the speed of motion of the object. Usually the default is fine (and each object has its own default delay option for optimal aesthetics).


Show the user something while we unpack the archive:

    my $sp = new Term::Twiddle;
    system('tar', '-zxf', '/some/tarfile.tar.gz');

Show the user a bouncing ball while we modify their configuration file:

    my $sp = new Term::Twiddle( { type => 'bounce' } );

    ## there must not be any 'sleep' calls in this!



Scott Wiersdorf, <scott@perlcode.org>


  • Prolly won't run on platforms lacking setitimer. Will run on Cygwin/Win32 (reported by Zak Zebrowski--thanks!).


  • Thanks to Tom Christiansen for the timer code (found lurking in an old FAQ somewhere). He probably never had an idea that it would be part of one of the most useful modules on CPAN ;o)

    The timer code has since been replaced by Time::HiRes's setitimer function, but it is good to thank Mr. Christiansen for his goodness to Perl anyway.

  • "Drew" (drew@drewtaylor.com) from rt.cpan.org for suggesting the removal of 'use warnings' for the faithful 5.005 users.

  • Orignal swishing motion filched from Term::ReadKey's test.pl by Kenneth Albanowski (kjahds@kjahds.com). Danke!