The processes run at the same time, and whatever the first process writes is immediately available to the second process. This environment encourages a new kind of program, known as a 'filter' or 'pipe fitting'. A filter reads from standard input and writes to standard output, changing the data on the way. It needs no file management or user interface, and expects to work with other filters. This approach to software development is attractive to a reuse-conscious developers.
Filters have tight cohesion but loose coupling.
The most mature filters are well-documented and widely known. You can build a filter without following any complex rules. On the other hand, there are some disadvantages. Pipework tries to bring the benefits to this technology to application software design, using the power of Eiffel to overcome the limitations of the Unix model. Objectives Pipework is intended to serve a wide variety of applications in many ways.