\section{\module{user} ---         User-specific configuration hook} \declaremodule{standard}{user}\modulesynopsis{A standard way to reference user-specific modules.}  \indexii{.pythonrc.py}{file}\indexiii{user}{configuration}{file} As a policy, Python doesn't run user-specified code on startup ofPython programs.  (Only interactive sessions execute the scriptspecified in the \envvar{PYTHONSTARTUP} environment variable if itexists). However, some programs or sites may find it convenient to allow usersto have a standard customization file, which gets run when a programrequests it.  This module implements such a mechanism.  A programthat wishes to use the mechanism must execute the statement \begin{verbatim}import user\end{verbatim} The \module{user} module looks for a file \file{.pythonrc.py} in the user'shome directory and if it can be opened, executes it (using\function{execfile()}\bifuncindex{execfile}) in its own (themodule \module{user}'s) global namespace.  Errors during this phaseare not caught; that's up to the program that imports the\module{user} module, if it wishes.  The home directory is assumed tobe named by the \envvar{HOME} environment variable; if this is not set,the current directory is used. The user's \file{.pythonrc.py} could conceivably test for\code{sys.version} if it wishes to do different things depending onthe Python version. A warning to users: be very conservative in what you place in your\file{.pythonrc.py} file.  Since you don't know which programs willuse it, changing the behavior of standard modules or functions isgenerally not a good idea. A suggestion for programmers who wish to use this mechanism: a simpleway to let users specify options for your package is to have themdefine variables in their \file{.pythonrc.py} file that you test inyour module.  For example, a module \module{spam} that has a verbositylevel can look for a variable \code{user.spam_verbose}, as follows: \begin{verbatim}import user verbose = bool(getattr(user, "spam_verbose", 0))\end{verbatim} (The three-argument form of \function{getattr()} is used in casethe user has not defined \code{spam_verbose} in their\file{.pythonrc.py} file.) Programs with extensive customization needs are better off reading aprogram-specific customization file. Programs with security or privacy concerns should \emph{not} importthis module; a user can easily break into a program by placingarbitrary code in the \file{.pythonrc.py} file. Modules for general use should \emph{not} import this module; it mayinterfere with the operation of the importing program. \begin{seealso}  \seemodule{site}{Site-wide customization mechanism.}\end{seealso}