For options which can be repeated like ``--verbose`` and ``--quite``,

a nonnegative integer could be used to represent the level to be specified:

..code-block::ini

It is possible to append values to a section within a configuration file such as the pip.ini file.

This is applicable to appending options like ``--find-links`` or ``--trusted-host``,

which can be written on multiple lines:

format ``PIP_<UPPER_LONG_NAME>`` . Dashes (``-``) have to be replaced with

underscores (``_``).

For example, to set the default timeout::

This is the same as passing the option to pip directly::

For example, setting ``PIP_DEFAULT_TIMEOUT`` to 60 has the same effect as

passing the option to pip directly::

For command line options which can be repeated,use a space to separate

For command line options which can be repeated,if they do not take any argument

is the same as calling::

Fruitful repeatable options however, can be specified via environment variable

as a space-separated list. For example having ``PIP_FIND_LINKS`` set to

``"http://mirror1.example.com http://mirror2.example.com"`` is the same as

calling ::