Along the way to measure the performance of a Smalltalk implementation for commodity multi-core systems, I tried to use Pharo as a more convenient development platform. Well, and I failed in the first attempt…

To remind myself and document some of the necessary steps in this environment, I wrote up the following tutorial.

Command-line Scripts with a Headless Pharo

For some tasks like benchmarking and automated testing, an integration with other tools comes in handy. For such use cases, Pharo can be used headless, i.e., without its graphical user interface.

This brief tutorial will demonstrate how to use the Debian Language Shootout benchmarks with a fresh Pharo image.

Step 1: Setup Pharo and a Fresh Image

  • download a Pharo image, the sources file, and a VM from the download page
  • extract all archives in the same folder
  • start Pharo, from the commandline, on a MacOSX it should look like this: "Squeak VM Opt" \ pharo1.0-10418-BETAdev09.08.3.image

Step 2: Load OSProcess

For output on the shell, we need an extra package from the SqueakSource repository.

It can be loaded by simply executing the following code in a workspace window:

  loadLatestPackage: 'OSProcess'
               from: ''

To execute this code snippet, select it and press cmd+d or use the “do it” item in the context menu.

Step 3: Load Common Benchmark Code

Now we can load the common parts of all shootout benchmarks into our image.

  • On way to do this is to grab the code shown here and save it to a file called
  • Open the file browser from the Menu -> Tools -> File Browser.
  • Select and press filein to load the code.

Now you can close all windows in your image and save and quit it.

Step 4: Run a Benchmark

  • Grab the code of a benchmark like Fannkuch
  • Save it to a file named like
  • Add a run script to the end of the code in, like this:
Tests fannkuch.
SmalltalkImage current snapshot: false andQuit: true.
  • Run it with a headless Pharo:
"Squeak VM Opt" \
    -headless pharo1.0-10418-BETAdev09.08.3.image \
    $PWD/ 6

important is here the absolute path to the script, clearly inconvenient and uncommon on the command-line.