Enable tab-completion in Python Shell

1. Create the file ~/.pyrc with the following content:

   $ cat .pyrc
   # ~/.pyrc
   # enable syntax completion
   try:
       import readline
   except ImportError:
       print "Module readline not available."
   else:
       import rlcompleter
       readline.parse_and_bind("tab: complete")
   

If you are only using it on Linux, this try is not really necessary. I put it around the import readline, as it uses the GNU readline library, which may have some issues outside of Linux.

2. Export the variable read every time a Python shell is opened (use full path with /home/user):

   julio@julio-acer ~> export PYTHONSTARTUP="/home/julio/.pyrc"
   

3. Insert the same line in the .bashrc and .zshrc files, so the variable is always initialized. In csh, variable assignment is different. Add the following line to ~/.cshrc:

   setenv PYTHONSTARTUP ~/.pythonrc"
   

4. Ready! Press the TAB key to display the list of possible completions:

   $ python
   Python 3.2.2 (default, Sep  5 2011, 04:52:19)
   [GCC 4.6.1 20110819 (prerelease)] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import re
   >>> re.
   re.A                  re.__eq__(            re._compile(
   re.ASCII              re.__file__           re._compile_repl(
   re.DEBUG              re.__format__(        re._compile_typed(
   re.DOTALL             re.__ge__(            re._expand(
   re.I                  re.__getattribute__(  re._pattern_type(
   re.IGNORECASE         re.__gt__(            re._pickle(
   re.L                  re.__hash__(          re._subx(
   re.LOCALE             re.__init__(          re.compile(
   re.M                  re.__le__(            re.copyreg
   re.MULTILINE          re.__lt__(            re.error(
   re.S                  re.__name__           re.escape(
   re.Scanner(           re.__ne__(            re.findall(
   re.T                  re.__new__(           re.finditer(
   re.TEMPLATE           re.__package__        re.functools
   re.U                  re.__reduce__(        re.match(
   re.UNICODE            re.__reduce_ex__(     re.purge(
   re.VERBOSE            re.__repr__(          re.search(
   re.X                  re.__setattr__(       re.split(
   re.__all__            re.__sizeof__(        re.sre_compile
   re.__cached__         re.__str__(           re.sre_parse
   re.__class__(         re.__subclasshook__(  re.sub(
   re.__delattr__(       re.__version__        re.subn(
   re.__dict__           re._alphanum_bytes    re.sys
   re.__doc__            re._alphanum_str      re.template(
   

Alternatives

There are enhanced Python Shells, such as iPython. It is quite simple, interactive, and contains several interesting features, including autocompletion.

The official wiki suggests some others.