\section{Invoking the Interpreter}
-The Python interpreter is usually installed as {\tt /usr/local/python}
-on those machines where it is available; putting {\tt /usr/local} in
+The Python interpreter is usually installed as {\tt /usr/local/bin/python}
+on those machines where it is available; putting {\tt /usr/local/bin} in
your {\UNIX} shell's search path makes it possible to start it by
typing the command
to the shell. Since the choice of the directory where the interpreter
lives is an installation option, other places are possible; check with
your local Python guru or system administrator. (E.g., {\tt
-/usr/local/bin/python} is a popular alternative location.)
+/usr/local/python} is a popular alternative location.)
The interpreter operates somewhat like the {\UNIX} shell: when called
with standard input connected to a tty device, it reads and executes
\bcode\begin{verbatim}
python
-Python 0.9.5 (Jan 2 1992).
+Python 0.9.7 (Aug 28 1992).
Copyright 1990, 1991, 1992 Stichting Mathematisch Centrum, Amsterdam
>>>
\end{verbatim}\ecode
for a file named {\tt foo.py} in the list of directories specified by
the environment variable {\tt PYTHONPATH}. It has the same syntax as
the {\UNIX} shell variable {\tt PATH}, i.e., a list of colon-separated
-directory names. When {\tt PYTHONPATH} is not set, an
-installation-dependent default path is used, usually {\tt
-.:/usr/local/lib/python}.
+directory names. When {\tt PYTHONPATH} is not set, or when the file
+is not found there, the search continues in an installation-dependent
+default path, usually {\tt .:/usr/local/lib/python}.
Actually, modules are searched in the list of directories given by the
-variable {\tt sys.path} which is initialized from {\tt PYTHONPATH} or
+variable {\tt sys.path} which is initialized from {\tt PYTHONPATH} and
the installation-dependent default. This allows Python programs that
know what they're doing to modify or replace the module search path.
See the section on Standard Modules later.
executable, like shell scripts, by putting the line
\bcode\begin{verbatim}
-#! /usr/local/python
+#! /usr/local/bin/python
\end{verbatim}\ecode
%
(assuming that's the name of the interpreter) at the beginning of the
script and giving the file an executable mode. The {\tt \#!} must be
the first two characters of the file.
+\subsection{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 {\tt
+PYTHONSTARTUP} to the name of a file containing your start-up
+commands. This is similar to the {\tt /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 {\tt /dev/tty} is given as the
+explicit source of commands (which otherwise behaves like an
+interactive session). It is executed in the same name space where
+interactive commands are executed, so that objects that it defines or
+imports can be used without qualification in the interactive session.
+
+If you want to read an additional start-up file from the current
+directory, you can program this in the global start-up file, e.g.
+\verb\execfile('.pythonrc')\. If you want to use the startup file
+in a script, you must write this explicitly in the script, e.g.
+\verb\import os;\ \verb\execfile(os.environ['PYTHONSTARTUP'])\.
+
\section{Interactive Input Editing and History Substitution}
Some versions of the Python interpreter support editing of the current
\section{Invoking the Interpreter}
-The Python interpreter is usually installed as {\tt /usr/local/python}
-on those machines where it is available; putting {\tt /usr/local} in
+The Python interpreter is usually installed as {\tt /usr/local/bin/python}
+on those machines where it is available; putting {\tt /usr/local/bin} in
your {\UNIX} shell's search path makes it possible to start it by
typing the command
to the shell. Since the choice of the directory where the interpreter
lives is an installation option, other places are possible; check with
your local Python guru or system administrator. (E.g., {\tt
-/usr/local/bin/python} is a popular alternative location.)
+/usr/local/python} is a popular alternative location.)
The interpreter operates somewhat like the {\UNIX} shell: when called
with standard input connected to a tty device, it reads and executes
\bcode\begin{verbatim}
python
-Python 0.9.5 (Jan 2 1992).
+Python 0.9.7 (Aug 28 1992).
Copyright 1990, 1991, 1992 Stichting Mathematisch Centrum, Amsterdam
>>>
\end{verbatim}\ecode
for a file named {\tt foo.py} in the list of directories specified by
the environment variable {\tt PYTHONPATH}. It has the same syntax as
the {\UNIX} shell variable {\tt PATH}, i.e., a list of colon-separated
-directory names. When {\tt PYTHONPATH} is not set, an
-installation-dependent default path is used, usually {\tt
-.:/usr/local/lib/python}.
+directory names. When {\tt PYTHONPATH} is not set, or when the file
+is not found there, the search continues in an installation-dependent
+default path, usually {\tt .:/usr/local/lib/python}.
Actually, modules are searched in the list of directories given by the
-variable {\tt sys.path} which is initialized from {\tt PYTHONPATH} or
+variable {\tt sys.path} which is initialized from {\tt PYTHONPATH} and
the installation-dependent default. This allows Python programs that
know what they're doing to modify or replace the module search path.
See the section on Standard Modules later.
executable, like shell scripts, by putting the line
\bcode\begin{verbatim}
-#! /usr/local/python
+#! /usr/local/bin/python
\end{verbatim}\ecode
%
(assuming that's the name of the interpreter) at the beginning of the
script and giving the file an executable mode. The {\tt \#!} must be
the first two characters of the file.
+\subsection{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 {\tt
+PYTHONSTARTUP} to the name of a file containing your start-up
+commands. This is similar to the {\tt /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 {\tt /dev/tty} is given as the
+explicit source of commands (which otherwise behaves like an
+interactive session). It is executed in the same name space where
+interactive commands are executed, so that objects that it defines or
+imports can be used without qualification in the interactive session.
+
+If you want to read an additional start-up file from the current
+directory, you can program this in the global start-up file, e.g.
+\verb\execfile('.pythonrc')\. If you want to use the startup file
+in a script, you must write this explicitly in the script, e.g.
+\verb\import os;\ \verb\execfile(os.environ['PYTHONSTARTUP'])\.
+
\section{Interactive Input Editing and History Substitution}
Some versions of the Python interpreter support editing of the current
projects / thirdparty / Python / cpython.git / commitdiff
