Writing your own sort can be a good exercise in learning Perl. Developing your own algorithm is surprisingly difficult and error-prone and adds little or nothing to the objective. There are several 'classic' algorithms. Each has its own advantages. Bubble-sort is almost certainly the easiest to understand and implement. This makes it a good candidate for your first sort routine. Find a specification (A flow chart, a detailed description, or perhaps an implementation in another language). When you understand the algorithm, it is time to start writing your Perl implementation. After you have finished, you may wish to create a second version making use of knowledge you have gained. At this point, you are ready to repeat the whole process with an algorithm better suited to the task you have in mind. Ask questions as they come up. Try to keep them very specific.