# 16.11 `pipes` -- Interface to shell pipelines

Availability: Unix.

The `pipes` module defines a class to abstract the concept of a pipeline -- a sequence of converters from one file to another.

Because the module uses /bin/sh command lines, a POSIX or compatible shell for `os.system()` and `os.popen()` is required.

The `pipes` module defines the following class:

class `Template`( | )

  An abstraction of a pipeline.

Example:

    >>> import pipes
    >>> t=pipes.Template()
    >>> t.append('tr a-z A-Z', '--')
    >>> f=t.open('/tmp/1', 'w')
    >>> f.write('hello world')
    >>> f.close()
    >>> open('/tmp/1').read()
    'HELLO WORLD'