--- /dev/null
- #!/usr/bin/env python3.4
+ .. _tut-appendix:
+
+ ********
+ Appendix
+ ********
+
+
+ .. _tut-interac:
+
+ Interactive Mode
+ ================
+
+ .. _tut-error:
+
+ Error Handling
+ --------------
+
+ When an error occurs, the interpreter prints an error message and a stack trace.
+ In interactive mode, it then returns to the primary prompt; when input came from
+ a file, it exits with a nonzero exit status after printing the stack trace.
+ (Exceptions handled by an :keyword:`except` clause in a :keyword:`try` statement
+ are not errors in this context.) Some errors are unconditionally fatal and
+ cause an exit with a nonzero exit; this applies to internal inconsistencies and
+ some cases of running out of memory. All error messages are written to the
+ standard error stream; normal output from executed commands is written to
+ standard output.
+
+ Typing the interrupt character (usually Control-C or DEL) to the primary or
+ secondary prompt cancels the input and returns to the primary prompt. [#]_
+ Typing an interrupt while a command is executing raises the
+ :exc:`KeyboardInterrupt` exception, which may be handled by a :keyword:`try`
+ statement.
+
+
+ .. _tut-scripts:
+
+ Executable Python Scripts
+ -------------------------
+
+ On BSD'ish Unix systems, Python scripts can be made directly executable, like
+ shell scripts, by putting the line ::
+
- '/home/user/.local/lib/python3.4/site-packages'
++ #!/usr/bin/env python3.5
+
+ (assuming that the interpreter is on the user's :envvar:`PATH`) at the beginning
+ of the script and giving the file an executable mode. The ``#!`` must be the
+ first two characters of the file. On some platforms, this first line must end
+ with a Unix-style line ending (``'\n'``), not a Windows (``'\r\n'``) line
+ ending. Note that the hash, or pound, character, ``'#'``, is used to start a
+ comment in Python.
+
+ The script can be given an executable mode, or permission, using the
+ :program:`chmod` command.
+
+ .. code-block:: bash
+
+ $ chmod +x myscript.py
+
+ On Windows systems, there is no notion of an "executable mode". The Python
+ installer automatically associates ``.py`` files with ``python.exe`` so that
+ a double-click on a Python file will run it as a script. The extension can
+ also be ``.pyw``, in that case, the console window that normally appears is
+ suppressed.
+
+
+ .. _tut-startup:
+
+ The Interactive Startup File
+ ----------------------------
+
+ When you use Python interactively, it is frequently handy to have some standard
+ commands executed every time the interpreter is started. You can do this by
+ setting an environment variable named :envvar:`PYTHONSTARTUP` to the name of a
+ file containing your start-up commands. This is similar to the :file:`.profile`
+ feature of the Unix shells.
+
+ This file is only read in interactive sessions, not when Python reads commands
+ from a script, and not when :file:`/dev/tty` is given as the explicit source of
+ commands (which otherwise behaves like an interactive session). It is executed
+ in the same namespace where interactive commands are executed, so that objects
+ that it defines or imports can be used without qualification in the interactive
+ session. You can also change the prompts ``sys.ps1`` and ``sys.ps2`` in this
+ file.
+
+ If you want to read an additional start-up file from the current directory, you
+ can program this in the global start-up file using code like ``if
+ os.path.isfile('.pythonrc.py'): exec(open('.pythonrc.py').read())``.
+ If you want to use the startup file in a script, you must do this explicitly
+ in the script::
+
+ import os
+ filename = os.environ.get('PYTHONSTARTUP')
+ if filename and os.path.isfile(filename):
+ with open(filename) as fobj:
+ startup_file = fobj.read()
+ exec(startup_file)
+
+
+ .. _tut-customize:
+
+ The Customization Modules
+ -------------------------
+
+ Python provides two hooks to let you customize it: :mod:`sitecustomize` and
+ :mod:`usercustomize`. To see how it works, you need first to find the location
+ of your user site-packages directory. Start Python and run this code::
+
+ >>> import site
+ >>> site.getusersitepackages()
++ '/home/user/.local/lib/python3.5/site-packages'
+
+ Now you can create a file named :file:`usercustomize.py` in that directory and
+ put anything you want in it. It will affect every invocation of Python, unless
+ it is started with the :option:`-s` option to disable the automatic import.
+
+ :mod:`sitecustomize` works in the same way, but is typically created by an
+ administrator of the computer in the global site-packages directory, and is
+ imported before :mod:`usercustomize`. See the documentation of the :mod:`site`
+ module for more details.
+
+
+ .. rubric:: Footnotes
+
+ .. [#] A problem with the GNU Readline package may prevent this.