root@zengl:~# python
Python 2.6.6 (r266:84292, Nov 27 2010, 19:47:39) 
[GCC 4.5.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> quit()
root@zengl:~# 

[email protected]:~/Downloads$ tar -zxvf Python-2.7.8.tgz 
[email protected]:~/Downloads$ cd Python-2.7.8
[email protected]:~/Downloads/Python-2.7.8$ ls
config.guess  Doc         LICENSE          Objects        Python
config.sub    Grammar     Mac              Parser         README
configure     Include     Makefile.pre.in  PC             RISCOS
configure.ac  install-sh  Misc             PCbuild        setup.py
Demo          Lib         Modules          pyconfig.h.in  Tools
[email protected]:~/Downloads/Python-2.7.8$ ./configure 
[email protected]:~/Downloads/Python-2.7.8$ make
[email protected]:~/Downloads/Python-2.7.8$ sudo make install
[sudo] password for zengl: 
[email protected]:~/Downloads/Python-2.7.8$ python
Python 2.7.8 (default, Nov 26 2014, 11:28:30) 
[GCC 4.5.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> quit()
[email protected]:~/Downloads/Python-2.7.8$ 

zengl@zengl-VirtualBox:~$ pdb.py
pdb.py：未找到命令
zengl@zengl-VirtualBox:~$ export PATH="$PATH:/usr/local/lib/python2.7"
zengl@zengl-VirtualBox:~$ echo $PATH
/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/lib/python2.7
zengl@zengl-VirtualBox:~$ pdb.py 
usage: pdb.py scriptfile [arg] ...
zengl@zengl-VirtualBox:~$ 

C:\Users\Administrator>PATH %PATH%;D:\Python

C:\Users\Administrator>PATH
PATH=C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32
\WindowsPowerShell\v1.0\;C:\Program Files\ATI Technologies\ATI.ACE\Core-Static;D
:\cygwin\bin;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Fi
les\Microsoft SQL Server\100\DTS\Binn\;D:\Python

C:\Users\Administrator>python
Python 2.7.8 (default, Jun 30 2014, 16:03:49) [MSC v.1500 32 bit (Intel)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> quit()

C:\Users\Administrator>

C:\Users\Administrator>PATH %PATH%;D:\Python\Lib

C:\Users\Administrator>PATH
PATH=C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32
\WindowsPowerShell\v1.0\;C:\Program Files\ATI Technologies\ATI.ACE\Core-Static;D
:\cygwin\bin;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Fi
les\Microsoft SQL Server\100\DTS\Binn\;D:\Python;D:\Python\Lib

C:\Users\Administrator>pdb.py
usage: pdb.py scriptfile [arg] ...

[email protected]:~$ python -h
usage: python [option] ... [-c cmd | -m mod | file | -] [arg] ...
Options and arguments (and corresponding environment variables):
-B     : don't write .py[co] files on import; also PYTHONDONTWRITEBYTECODE=x
-c cmd : program passed in as string (terminates option list)
-d     : debug output from parser; also PYTHONDEBUG=x
-E     : ignore PYTHON* environment variables (such as PYTHONPATH)
-h     : print this help message and exit (also --help)
-i     : inspect interactively after running script; forces a prompt even
         if stdin does not appear to be a terminal; also PYTHONINSPECT=x
-m mod : run library module as a script (terminates option list)
-O     : optimize generated bytecode slightly; also PYTHONOPTIMIZE=x
-OO    : remove doc-strings in addition to the -O optimizations
-R     : use a pseudo-random salt to make hash() values of various types be
         unpredictable between separate invocations of the interpreter, as
         a defense against denial-of-service attacks
-Q arg : division options: -Qold (default), -Qwarn, -Qwarnall, -Qnew
-s     : don't add user site directory to sys.path; also PYTHONNOUSERSITE
-S     : don't imply 'import site' on initialization
-t     : issue warnings about inconsistent tab usage (-tt: issue errors)
-u     : unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x
         see man page for details on internal buffering relating to '-u'
-v     : verbose (trace import statements); also PYTHONVERBOSE=x
         can be supplied multiple times to increase verbosity
-V     : print the Python version number and exit (also --version)
-W arg : warning control; arg is action:message:category:module:lineno
         also PYTHONWARNINGS=arg
-x     : skip first line of source, allowing use of non-Unix forms of #!cmd
-3     : warn about Python 3.x incompatibilities that 2to3 cannot trivially fix
file   : program read from script file
-      : program read from stdin (default; interactive mode if a tty)
arg ...: arguments passed to program in sys.argv[1:]

Other environment variables:
PYTHONSTARTUP: file executed on interactive startup (no default)
PYTHONPATH   : ':'-separated list of directories prefixed to the
               default module search path.  The result is sys.path.
PYTHONHOME   : alternate  directory (or :).
               The default module search path uses /pythonX.X.
PYTHONCASEOK : ignore case in 'import' statements (Windows).
PYTHONIOENCODING: Encoding[:errors] used for stdin/stdout/stderr.
PYTHONHASHSEED: if this variable is set to 'random', the effect is the same
   as specifying the -R option: a random value is used to seed the hashes of
   str, bytes and datetime objects.  It can also be set to an integer
   in the range [0,4294967295] to get hash values with a predictable seed.
[email protected]:~$ 

[email protected]:~$ python -c "print 'hello python';"
hello python
[email protected]:~$ 

[email protected]:~$ python -V
Python 2.7.8
[email protected]:~$