[base]
name=CentOS-$releasever - Base
baseurl=http://mirrors.163.com/centos/6/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://mirrors.163.com/centos/6/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#packages used/produced in the build but not released
#[addons]
#name=CentOS-$releasever - Addons
#baseurl=http://mirrors.163.com/centos/$releasever/addons/$basearch/
#gpgcheck=1
#gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=http://mirrors.163.com/centos/6/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
baseurl=http://mirrors.163.com/centos/6/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6

{
  "android": {
    "release": {
      "keystore": "release-key.keystore",
      "alias": "cordova-demo",
      "storePassword": "password",
      "password": "password"
    }
  }
}

import android.webkit.WebSettings;
import android.webkit.WebView;
@Override
protected void onResume() {
    super.onResume();
    // Disable caching ..
    WebView wv = (WebView) appView.getEngine().getView();
    WebSettings ws = wv.getSettings();
    ws.setAppCacheEnabled(false);
    ws.setCacheMode(WebSettings.LOAD_NO_CACHE);
    loadUrl(launchUrl); // launchUrl is the default url specified in Config.xml
}

zip -r tmpfile.zip testfolder

split -b 5m tmpfile.zip splitfile-

nowdate=`date +%Y%m%d`;n=0; for filename in `ls splitfile* `; do n=`expr ${n} + 1`; suffix=`printf %04d ${n}`; mv ${filename} ${nowdate}_zzzz_RetentionPhotosSync_iiii_${suffix}.zip ; done

rm tmpfile.zip

cat yyyymmdd_zzzz_RetentionPhotosSync_iiii_*.zip > yyyymmdd_zzzz_RetentionPhotosSync_iiii.zip

unzip yyyymmdd_zzzz_RetentionPhotosSync_iiii.zip

./srelay -i xxx.xxx.xxx.xxx:31080  

vi Makefile
PREFIX = /path/to/your/app
BINDIR = $(PREFIX)/bin
MANDIR = $(PREFIX)/man
INFODIR = $(PREFIX)/info
LOCAL_ROOT = $(PREFIX)/www
DISK_CACHE_ROOT = $(PREFIX)/cache

vi config
socksParentProxy = "xxx.xxx.xxx.xxx:31080"
socksProxyType = socks5
proxyAddress = "0.0.0.0"
proxyPort = 31081

nohup ./polipo -c config

export http_proxy="http://xxx.xxx.xxx.xxx:31081"

wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-urlgrabber-3.9.1-11.el6.noarch.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-3.2.29-73.el6.centos.noarch.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-37.el6.noarch.rpm\

rpm -qa | grep yum | xargs rpm -e --nodeps
rpm -ivh python-iniparse-0.3.1-2.1.el6.noarch.rpm
rpm -ivh yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
rpm -ivh python-urlgrabber-3.9.1-11.el6.noarch.rpm --force
rpm -ivh yum-3.2.29-73.el6.centos.noarch.rpm yum-plugin-fastestmirror-1.1.30-37.el6.noarch.rpm

wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
yum clean all
yum makecache

wget https://www.python.org/ftp/python/3.6.0/Python-3.6.0.tgz
tar -zxcf Python-3.6.0.tgz
./configure
make && make install

alias pip3="pip3 --proxy 134.32.32.13:31081"
export http_proxy=134.32.32.13:31081
export https_proxy=134.32.32.13:31081

pip3 install requests
pip3 install beautifulsoup4
pip3 install mysql-connector
pip3 install fdfs_client-py

git clone https://github.com/jefforeilly/fdfs_client-py.git
cd dfs_client-py
vi ./fdfs_client/storage_client.py
将第12行 from fdfs_client.sendfile import * 注释掉
python3 setup.py install

export http_proxy="http://xxx.xxx.xxx.xxx:31081"
export https_proxy="http://xxx.xxx.xxx.xxx:31081"

yum -y install nano zip unzip libyaml-devel zlib-devel curl-devel openssl-devel httpd-devel apr-devel apr-util-devel mysql-devel gcc ruby-devel gcc-c++ make postgresql-devel ImageMagick-devel sqlite-devel perl-LDAP mod_perl perl-Digest-SHA

yum -y install mysql mysql-server

chkconfig mysqld on
service mysqld start

/usr/bin/mysql_secure_installation

Enter current password for root (enter for none):
Set root password? [Y/n] y
Remove anonymous users? [Y/n] y
Disallow root login remotely? [Y/n] n
Remove test database and access to it? [Y/n] y
Reload privilege tables now? [Y/n] y

mysql -uroot -p
> create database redmine_db character set utf8;
> create user 'redmine_admin'@'localhost' identified by 'your_new_password';
> grant all privileges on redmine_db.* to 'redmine_admin'@'localhost';

vi /etc/selinux/config
SELINUX=disabled

/usr/sbin/setenforce 0 立刻关闭

vi /etc/sysconfig/iptables

-A INPUT -m state --state NEW -m tcp -p tcp --dport 3000 -j ACCEPT

/etc/init.d/iptables restart

curl -L https://get.rvm.io | bash
source /etc/profile.d/rvm.sh

rvm list known

rvm install 2.3.0

ruby -v
ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-linux]

yum -y install rubygems

wget http://www.redmine.org/releases/redmine-3.3.2.tar.gz
tar -zxvf redmine-3.3.2.tar.gz
mv redmine-3.3.2 redmine

cd /path/to/redmine/config
cp database.yml.example database.yml

vi database.yml

production:
  adapter: mysql2
  database: redmine_db
  host: localhost
  username: redmine_admin
  password: "redmine_password"
  encoding: utf8

gem install bundler
bundle install
rake generate_secret_token

RAILS_ENV=production rake db:migrate
RAILS_ENV=production rake redmine:load_default_data

mkdir -p tmp tmp/pdf public/plugin_assets
sudo chown -R redmine:redmine files log tmp public/plugin_assets
sudo chmod -R 755 files log tmp public/plugin_assets

bundle exec rails server -b 0.0.0.0 webrick -e production -d

Yes: if foo:
         bar()
     while x:
         x = bar()
     if x and y:
         bar()
     if not x:
         bar()
     return foo
     for (x, y) in dict.items(): ...

No:  if (x):
        bar()
    if not(x):
        bar()
    return (foo)

Yes: spam(ham[1], {eggs: 2}, [])

No:  spam( ham[ 1 ], { eggs: 2 }, [ ] )

Yes: if x == 4:
         print x, y
     x, y = y, x

No:  if x == 4 :
         print x , y
     x , y = y , x

Yes: spam(1)

no: spam (1)

Yes: dict['key'] = list[index]

No:  dict ['key'] = list [index]

Yes: x == 1

No:  x<1

Yes: def complex(real, imag=0.0): return magic(r=real, i=imag)

No:  def complex(real, imag = 0.0): return magic(r = real, i = imag)

Yes:
     foo = 1000  # comment
     long_name = 2  # comment that should not be aligned

     dictionary = {
         "foo": 1,
         "long_name": 2,
         }

No:
     foo       = 1000  # comment
     long_name = 2     # comment that should not be aligned

     dictionary = {
         "foo"      : 1,
         "long_name": 2,
         }

def fetch_bigtable_rows(big_table, keys, other_silly_variable=None):
    """Fetches rows from a Bigtable.

    Retrieves rows pertaining to the given keys from the Table instance
    represented by big_table.  Silly things may happen if
    other_silly_variable is not None.

    Args:
        big_table: An open Bigtable Table instance.
        keys: A sequence of strings representing the key of each table row
            to fetch.
        other_silly_variable: Another optional variable, that has a much
            longer name than the other args, and which does nothing.

    Returns:
        A dict mapping keys to the corresponding table row data
        fetched. Each row is represented as a tuple of strings. For
        example:

        {'Serak': ('Rigel VII', 'Preparer'),
         'Zim': ('Irk', 'Invader'),
         'Lrrr': ('Omicron Persei 8', 'Emperor')}

        If a key from the keys argument is missing from the dictionary,
        then that row was not found in the table.

    Raises:
        IOError: An error occurred accessing the bigtable.Table object.
    """
    pass

class SampleClass(object):
    """Summary of class here.

    Longer class information....
    Longer class information....

    Attributes:
        likes_spam: A boolean indicating if we like SPAM or not.
        eggs: An integer count of the eggs we have laid.
    """

    def __init__(self, likes_spam=False):
        """Inits SampleClass with blah."""
        self.likes_spam = likes_spam
        self.eggs = 0

    def public_method(self):
        """Performs operation blah."""

# We use a weighted dictionary search to find out where i is in
# the array.  We extrapolate position based on the largest num
# in the array and the array size and then do binary search to
# get the exact number.

if i & (i-1) == 0:        # true iff i is a power of 2

Yes: class SampleClass(object):
         pass


     class OuterClass(object):

         class InnerClass(object):
             pass


     class ChildClass(ParentClass):
         """Explicitly inherits from another class already."""

No: class SampleClass:
        pass


    class OuterClass:

        class InnerClass:
            pass

Yes: x = a + b
     x = '%s, %s!' % (imperative, expletive)
     x = '{}, {}!'.format(imperative, expletive)
     x = 'name: %s; score: %d' % (name, n)
     x = 'name: {}; score: {}'.format(name, n)

No: x = '%s%s' % (a, b)  # use + in this case
    x = '{}{}'.format(a, b)  # use + in this case
    x = imperative + ', ' + expletive + '!'
    x = 'name: ' + name + '; score: ' + str(n)

Yes: items = ['<table>']
     for last_name, first_name in employee_list:
         items.append('<tr><td>%s, %s</td></tr>' % (last_name, first_name))
     items.append('</table>')
     employee_table = ''.join(items)

No: employee_table = '<table>'
    for last_name, first_name in employee_list:
        employee_table += '<tr><td>%s, %s</td></tr>' % (last_name, first_name)
    employee_table += '</table>'

Yes:
     Python('Why are you hiding your eyes?')
     Gollum("I'm scared of lint errors.")
     Narrator('"Good!" thought a happy Python reviewer.')

No:
     Python("Why are you hiding your eyes?")
     Gollum('The lint. It burns. It burns us.')
     Gollum("Always the great lint. Watching. Watching.")

Yes:
    print ("This is much nicer.\n"
           "Do it this way.\n")

No:
      print """This is pretty ugly.
  Don't do this.
  """

with open("hello.txt") as hello_file:
    for line in hello_file:
        print line

import contextlib

with contextlib.closing(urllib.urlopen("http://www.python.org/")) as front_page:
    for line in front_page:
        print line

# TODO(kl@gmail.com): Use a "*" here for string repetition.
# TODO(Zeke) Change this to use relations.

Yes: import os
     import sys

No:  import os, sys

import foo
from foo import bar
from foo.bar import baz
from foo.bar import Quux
from Foob import ar

Yes:

  if foo: bar(foo)

No:

  if foo: bar(foo)
  else:   baz(foo)

  try:               bar(foo)
  except ValueError: baz(foo)

  try:
      bar(foo)
  except ValueError: baz(foo)

module_name
package_name
ClassName
method_name
ExceptionName
function_name
GLOBAL_VAR_NAME
instance_var_name
function_parameter_name
local_var_name

def main():
      ...

if __name__ == '__main__':
    main()

print('hello, world')
name = input()

print('''line1
line2
line3''')

a = 123 # a是整数
print(a)
a = 'ABC' # a变为字符串
print(a)

>>> 10 / 3
3.3333333333333335

>>> 9 / 3
3.0

>>> 10 // 3
3

>>> 10 % 3
1

>>> ord('A')
65
>>> ord('中')
20013
>>> chr(66)
'B'
>>> chr(25991)
'文'

>>> len('ABC')
3
>>> len('中文')
2

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

>>> 'Hello, %s' % 'world'
'Hello, world'
>>> 'Hi, %s, you have $%d.' % ('Michael', 1000000)
'Hi, Michael, you have $1000000.'

>>> classmates = ['Michael', 'Bob', 'Tracy']
>>> classmates
['Michael', 'Bob', 'Tracy']

>>> len(classmates)
3

>>> classmates[0]
'Michael'
>>> classmates[1]
'Bob'
>>> classmates[2]
'Tracy'
>>> classmates[-1]
'Tracy'

>>> classmates.append('Adam')
>>> classmates
['Michael', 'Bob', 'Tracy', 'Adam']

>>> classmates.insert(1, 'Jack')
>>> classmates
['Michael', 'Jack', 'Bob', 'Tracy', 'Adam']

>>> classmates.pop()
'Adam'
>>> classmates
['Michael', 'Jack', 'Bob', 'Tracy']

>>> classmates.pop(1)
'Jack'
>>> classmates
['Michael', 'Bob', 'Tracy']

>>> classmates[1] = 'Sarah'
>>> classmates
['Michael', 'Sarah', 'Tracy']

>>> L = ['Apple', 123, True]

>>> s = ['python', 'java', ['asp', 'php'], 'scheme']
>>> len(s)
4

>>> classmates = ('Michael', 'Bob', 'Tracy')

>>> t = (1,)
>>> t
(1,)

age = 3
if age >= 18:
    print('adult')
elif age >= 6:
    print('teenager')
else:
    print('kid')

names = ['Michael', 'Bob', 'Tracy']
for name in names:
    print(name)

sum = 0
n = 99
while n > 0:
    sum = sum + n
    n = n - 2
print(sum)

>>> d = {'Michael': 95, 'Bob': 75, 'Tracy': 85}
>>> d['Michael']
95

>>> 'Thomas' in d
False

>>> d.pop('Bob')
75
>>> d
{'Michael': 95, 'Tracy': 85}

>>> s = set([1, 1, 2, 2, 3, 3])
>>> s
{1, 2, 3}

>>> s.add(4)
>>> s
{1, 2, 3, 4}
>>> s.add(4)
>>> s
{1, 2, 3, 4}

>>> s.remove(4)
>>> s
{1, 2, 3}

>>> abs(-20)
20
max(2, 3, 1, -5)
3

>>> int(12.34)
12
>>> float('12.34')
12.34
>>> str(1.23)
'1.23'
>>> str(100)
'100'
>>> bool(1)
True
>>> bool('')
False

def power(x):
    return x * x

def power(x, n=2):
    s = 1
    while n > 0:
        n = n - 1
        s = s * x
    return s

def calc(*numbers):
    sum = 0
    for n in numbers:
        sum = sum + n * n
    return sum

>>> calc(1, 2)
5
>>> calc()
0
>>> nums = [1, 2, 3]
>>> calc(*nums)
14

def person(name, age, **kw):
    print('name:', name, 'age:', age, 'other:', kw)

>>> person('Bob', 35, city='Beijing')
name: Bob age: 35 other: {'city': 'Beijing'}
>>> person('Adam', 45, gender='M', job='Engineer')
name: Adam age: 45 other: {'gender': 'M', 'job': 'Engineer'}

>>> extra = {'city': 'Beijing', 'job': 'Engineer'}
>>> person('Jack', 24, **extra)
name: Jack age: 24 other: {'city': 'Beijing', 'job': 'Engineer'}

def person(name, age, **kw):
    if 'city' in kw:
        # 有city参数
        pass
    if 'job' in kw:
        # 有job参数
        pass
    print('name:', name, 'age:', age, 'other:', kw)

def f1(a, b, c=0, *args, **kw):
    print('a =', a, 'b =', b, 'c =', c, 'args =', args, 'kw =', kw)

def f2(a, b, c=0, *, d, **kw):
    print('a =', a, 'b =', b, 'c =', c, 'd =', d, 'kw =', kw)

def fact(n):
    return fact_iter(n, 1)

def fact_iter(num, product):
    if num == 1:
        return product
    return fact_iter(num - 1, num * product)

>>> L = ['Michael', 'Sarah', 'Tracy', 'Bob', 'Jack']

>>> L[0:3]
['Michael', 'Sarah', 'Tracy']

>>> L[:3]
['Michael', 'Sarah', 'Tracy']

>>> L[-2:]
['Bob', 'Jack']

>>> L[-2:-1]
['Bob']

>>> L = list(range(100))
>>> L
[0, 1, 2, 3, ..., 99]

>>> L[:10:2]  # 前10个数，每两个取一个：
[0, 2, 4, 6, 8]

>>> L[::5]  # 所有数，每5个取一个
[0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95]

>>> L[:]  # 原样复制一个list
[0, 1, 2, 3, ..., 99]

>>> d = {'a': 1, 'b': 2, 'c': 3}
>>> for key in d:
...     print(key)
...
a
c
b

>>> d = {'x': 'A', 'y': 'B', 'z': 'C' }
>>> for k, v in d.items():
...     print(k, '=', v)
...
y = B
x = A
z = C

>>> for ch in 'ABC':
...     print(ch)
...
A
B
C

>>> from collections import Iterable
>>> isinstance('abc', Iterable) # str是否可迭代
True
>>> isinstance([1,2,3], Iterable) # list是否可迭代
True
>>> isinstance(123, Iterable) # 整数是否可迭代
False

>>> list(range(1, 11))
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

>>> [x * x for x in range(1, 11)]
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

>>> [x * x for x in range(1, 11) if x % 2 == 0]
[4, 16, 36, 64, 100]

>>> d = {'x': 'A', 'y': 'B', 'z': 'C' }
>>> [k + '=' + v for k, v in d.items()]
['y=B', 'x=A', 'z=C']

>>> L = ['Hello', 'World', 'IBM', 'Apple']
>>> [s.lower() for s in L]
['hello', 'world', 'ibm', 'apple']

>>> L = [x * x for x in range(10)]
>>> L
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
>>> g = (x * x for x in range(10))
>>> g
<generator object <genexpr> at 0x1022ef630>

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' a test module '

__author__ = 'Michael Liao'

import sys

def test():
    args = sys.argv
    if len(args)==1:
        print('Hello, world!')
    elif len(args)==2:
        print('Hello, %s!' % args[1])
    else:
        print('Too many arguments!')

if __name__=='__main__':
    test()

pip install Pillow

>>> import sys
>>> sys.path
['', '/Library/Frameworks/Python.framework/Versions/3.4/lib/python34.zip', '/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4', '/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/plat-darwin', '/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/lib-dynload', '/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages']

>>> import sys
>>> sys.path.append('/Users/michael/my_py_scripts')

class Student(object):

    def __init__(self, name, score):
        self.name = name
        self.score = score

>>> bart = Student('Bart Simpson', 59)
>>> bart.name
'Bart Simpson'
>>> bart.score
59

class Student(object):

    def __init__(self, name, score):
        self.name = name
        self.score = score

    def print_score(self):
        print('%s: %s' % (self.name, self.score))

>>> bart.print_score()
Bart Simpson: 59

class Student(object):

    def __init__(self, name, score):
        self.__name = name
        self.__score = score

    def print_score(self):
        print('%s: %s' % (self.__name, self.__score))

    def get_name(self):
        return self.__name

    def get_score(self):
        return self.__score

    def set_score(self, score):
        self.__score = score

class Animal(object):
    def run(self):
        print('Animal is running...')

class Dog(Animal):

    def run(self):
        print('Dog is running...')

class Cat(Animal):

    def run(self):
        print('Cat is running...')

>>> isinstance(a, list)
True
>>> isinstance(b, Animal)
True
>>> isinstance(c, Dog)
True

>>> type(123)
<class 'int'>
>>> type('str')
<class 'str'>
>>> type(None)
<type(None) 'NoneType'>
>>> type(abs)
<class 'builtin_function_or_method'>
>>> type(a)
<class '__main__.Animal'>

>>> import types
>>> def fn():
...     pass
...
>>> type(fn)==types.FunctionType
True
>>> type(abs)==types.BuiltinFunctionType
True
>>> type(lambda x: x)==types.LambdaType
True
>>> type((x for x in range(10)))==types.GeneratorType
True

>>> isinstance(h, Husky)
True
>>> isinstance('a', str)
True
>>> isinstance(123, int)
True
>>> isinstance(b'a', bytes)
True

>>> dir('ABC')
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']

>>> class Student(object):
...     name = 'Student'
...
>>> s = Student() # 创建实例s
>>> print(s.name) # 打印name属性，因为实例并没有name属性，所以会继续查找class的name属性
Student
>>> print(Student.name) # 打印类的name属性
Student
>>> s.name = 'Michael' # 给实例绑定name属性
>>> print(s.name) # 由于实例属性优先级比类属性高，因此，它会屏蔽掉类的name属性
Michael
>>> print(Student.name) # 但是类属性并未消失，用Student.name仍然可以访问
Student
>>> del s.name # 如果删除实例的name属性
>>> print(s.name) # 再次调用s.name，由于实例的name属性没有找到，类的name属性就显示出来了
Student

try:
    print('try...')
    r = 10 / 0
    print('result:', r)
except ZeroDivisionError as e:
    print('except:', e)
finally:
    print('finally...')
print('END')

def foo(s):
    n = int(s)
    assert n != 0, 'n is zero!'
    return 10 / n

def main():
    foo('0')

import logging

s = '0'
n = int(s)
logging.info('n = %d' % n)
print(10 / n)

$ python3 -m pdb err.py

>>> f = open('/Users/michael/test.txt', 'r')
>>> f.read()
'Hello, world!'
>>> f.close()

with open('/path/to/file', 'r') as f:
    print(f.read())

for line in f.readlines():
    print(line.strip())

>>> f = open('/Users/michael/test.jpg', 'rb')
>>> f.read()
b'\xff\xd8\xff\xe1\x00\x18Exif\x00\x00...' # 十六进制表示的字节

>>> f = open('/Users/michael/gbk.txt', 'r', encoding='gbk')
>>> f.read()
'测试'

>>> f = open('/Users/michael/test.txt', 'w')
>>> f.write('Hello, world!')
>>> f.close()

with open('/Users/michael/test.txt', 'w') as f:
    f.write('Hello, world!')

>>> import os
>>> os.name # 操作系统类型
'posix'

>>> os.uname()
posix.uname_result(sysname='Darwin', nodename='MichaelMacPro.local', release='14.3.0', version='Darwin Kernel Version 14.3.0: Mon Mar 23 11:59:05 PDT 2015; root:xnu-2782.20.48~5/RELEASE_X86_64', machine='x86_64')

>>> os.environ
environ({'VERSIONER_PYTHON_PREFER_32_BIT': 'no', 'TERM_PROGRAM_VERSION': '326', 'LOGNAME': 'michael', 'USER': 'michael', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/usr/local/mysql/bin', ...})

>>> os.environ.get('PATH')
'/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/usr/local/mysql/bin'
>>> os.environ.get('x', 'default')
'default'

# 查看当前目录的绝对路径:
>>> os.path.abspath('.')
'/Users/michael'
# 在某个目录下创建一个新目录，首先把新目录的完整路径表示出来:
>>> os.path.join('/Users/michael', 'testdir')
'/Users/michael/testdir'
# 然后创建一个目录:
>>> os.mkdir('/Users/michael/testdir')
# 删掉一个目录:
>>> os.rmdir('/Users/michael/testdir')

>>> os.path.split('/Users/michael/testdir/file.txt')
('/Users/michael/testdir', 'file.txt')

>>> os.path.splitext('/path/to/file.txt')
('/path/to/file', '.txt')


# 对文件重命名:
>>> os.rename('test.txt', 'test.py')
# 删掉文件:
>>> os.remove('test.py')

>>> from datetime import datetime
>>> now = datetime.now() # 获取当前datetime
>>> print(now)
2015-05-18 16:28:07.198690

>>> from datetime import datetime
>>> dt = datetime(2015, 4, 19, 12, 20) # 用指定日期时间创建datetime
>>> print(dt)
2015-04-19 12:20:00

>>> from datetime import datetime
>>> dt = datetime(2015, 4, 19, 12, 20) # 用指定日期时间创建datetime
>>> dt.timestamp() # 把datetime转换为timestamp
1429417200.0

>>> from datetime import datetime
>>> t = 1429417200.0
>>> print(datetime.fromtimestamp(t))
2015-04-19 12:20:00

>>> from datetime import datetime
>>> cday = datetime.strptime('2015-6-1 18:19:59', '%Y-%m-%d %H:%M:%S')
>>> print(cday)
2015-06-01 18:19:59

>>> from datetime import datetime
>>> now = datetime.now()
>>> print(now.strftime('%a, %b %d %H:%M'))
Mon, May 05 16:28

>>> from datetime import datetime, timedelta
>>> now = datetime.now()
>>> now
datetime.datetime(2015, 5, 18, 16, 57, 3, 540997)
>>> now + timedelta(hours=10)
datetime.datetime(2015, 5, 19, 2, 57, 3, 540997)
>>> now - timedelta(days=1)
datetime.datetime(2015, 5, 17, 16, 57, 3, 540997)
>>> now + timedelta(days=2, hours=12)
datetime.datetime(2015, 5, 21, 4, 57, 3, 540997)

>>> import base64
>>> base64.b64encode(b'binary\x00string')
b'YmluYXJ5AHN0cmluZw=='
>>> base64.b64decode(b'YmluYXJ5AHN0cmluZw==')
b'binary\x00string'

import hashlib
md5 = hashlib.md5()
md5.update('how to use md5 in python hashlib?'.encode('utf-8'))
print(md5.hexdigest())
d26a53750bc40b38b65a520292f69306

try:
    f = open('/path/to/file', 'r')
    f.read()
finally:
    if f:
        f.close()

with open('/path/to/file', 'r') as f:
    f.read()

class Query(object):

    def __init__(self, name):
        self.name = name

    def __enter__(self):
        print('Begin')
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        if exc_type:
            print('Error')
        else:
            print('End')

    def query(self):
        print('Query info about %s...' % self.name)

with Query('Bob') as q:
    q.query()

from contextlib import contextmanager

class Query(object):

    def __init__(self, name):
        self.name = name

    def query(self):
        print('Query info about %s...' % self.name)

@contextmanager
def create_query(name):
    print('Begin')
    q = Query(name)
    yield q
    print('End')


with create_query('Bob') as q:
    q.query()

@contextmanager
def tag(name):
    print("<%s>" % name)
    yield
    print("</%s>" % name)

with tag("h1"):
    print("hello")
    print("world")

<h1>
hello
world
</h1>

from contextlib import closing
from urllib.request import urlopen

with closing(urlopen('https://www.python.org')) as page:
    for line in page:
        print(line)

from urllib import request
with request.urlopen('https://api.douban.com/v2/book/2129650') as f:
    data = f.read()
    print('Status:', f.status, f.reason)
    for k, v in f.getheaders():
        print('%s: %s' % (k, v))
    print('Data:', data.decode('utf-8'))

from urllib import request, parse

print('Login to weibo.cn...')
email = input('Email: ')
passwd = input('Password: ')
login_data = parse.urlencode([
    ('username', email),
    ('password', passwd),
    ('entry', 'mweibo'),
    ('client_id', ''),
    ('savestate', '1'),
    ('ec', ''),
    ('pagerefer', 'https://passport.weibo.cn/signin/welcome?entry=mweibo&r=http%3A%2F%2Fm.weibo.cn%2F')
])

req = request.Request('https://passport.weibo.cn/sso/login')
req.add_header('Origin', 'https://passport.weibo.cn')
req.add_header('User-Agent', 'Mozilla/6.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/8.0 Mobile/10A5376e Safari/8536.25')
req.add_header('Referer', 'https://passport.weibo.cn/signin/login?entry=mweibo&res=wel&wm=3349&r=http%3A%2F%2Fm.weibo.cn%2F')

with request.urlopen(req, data=login_data.encode('utf-8')) as f:
    print('Status:', f.status, f.reason)
    for k, v in f.getheaders():
        print('%s: %s' % (k, v))
    print('Data:', f.read().decode('utf-8'))

sudo pip3 install pillow

from PIL import Image

# 打开一个jpg图像文件，注意是当前路径:
im = Image.open('test.jpg')
# 获得图像尺寸:
w, h = im.size
print('Original image size: %sx%s' % (w, h))
# 缩放到50%:
im.thumbnail((w//2, h//2))
print('Resize image to: %sx%s' % (w//2, h//2))
# 把缩放后的图像用jpeg格式保存:
im.save('thumbnail.jpg', 'jpeg')

from PIL import Image, ImageDraw, ImageFont, ImageFilter
import random

# 随机字母:
def rndChar():
    return chr(random.randint(65, 90))

# 随机颜色1:
def rndColor():
    return (random.randint(64, 255), random.randint(64, 255), random.randint(64, 255))

# 随机颜色2:
def rndColor2():
    return (random.randint(32, 127), random.randint(32, 127), random.randint(32, 127))

# 240 x 60:
width = 60 * 4
height = 60
image = Image.new('RGB', (width, height), (255, 255, 255))
# 创建Font对象:
font = ImageFont.truetype('Arial.ttf', 36)
# 创建Draw对象:
draw = ImageDraw.Draw(image)
# 填充每个像素:
for x in range(width):
    for y in range(height):
        draw.point((x, y), fill=rndColor())
# 输出文字:
for t in range(4):
    draw.text((60 * t + 10, 10), rndChar(), font=font, fill=rndColor2())
# 模糊:
image = image.filter(ImageFilter.BLUR)
image.save('code.jpg', 'jpeg')

from tkinter import *
import tkinter.messagebox as messagebox

class Application(Frame):
    def __init__(self, master=None):
        Frame.__init__(self, master)
        self.pack()
        self.createWidgets()

    def createWidgets(self):
        self.nameInput = Entry(self)
        self.nameInput.pack()
        self.alertButton = Button(self, text='Hello', command=self.hello)
        self.alertButton.pack()

    def hello(self):
        name = self.nameInput.get() or 'world'
        messagebox.showinfo('Message', 'Hello, %s' % name)

app = Application()
# 设置窗口标题:
app.master.title('Hello World')
# 主消息循环:
app.mainloop()

from email import encoders
from email.header import Header
from email.mime.text import MIMEText
from email.utils import parseaddr, formataddr

import smtplib

def _format_addr(s):
    name, addr = parseaddr(s)
    return formataddr((Header(name, 'utf-8').encode(), addr))

from_addr = input('From: ')
password = input('Password: ')
to_addr = input('To: ')
smtp_server = input('SMTP server: ')

msg = MIMEText('hello, send by Python...', 'plain', 'utf-8')
msg['From'] = _format_addr('Python爱好者 <%s>' % from_addr)
msg['To'] = _format_addr('管理员 <%s>' % to_addr)
msg['Subject'] = Header('来自SMTP的问候……', 'utf-8').encode()

# 邮件正文是MIMEText:
msg.attach(MIMEText('send with file...', 'plain', 'utf-8'))

# 添加附件就是加上一个MIMEBase，从本地读取一个图片:
with open('/Users/michael/Downloads/test.png', 'rb') as f:
    # 设置附件的MIME和文件名，这里是png类型:
    mime = MIMEBase('image', 'png', filename='test.png')
    # 加上必要的头信息:
    mime.add_header('Content-Disposition', 'attachment', filename='test.png')
    mime.add_header('Content-ID', '<0>')
    mime.add_header('X-Attachment-Id', '0')
    # 把附件的内容读进来:
    mime.set_payload(f.read())
    # 用Base64编码:
    encoders.encode_base64(mime)
    # 添加到MIMEMultipart:
    msg.attach(mime)

server = smtplib.SMTP(smtp_server, 25)
server.set_debuglevel(1)
server.login(from_addr, password)
server.sendmail(from_addr, [to_addr], msg.as_string())
server.quit()

sudo pip3 install mysql-connector

# 导入MySQL驱动:
>>> import mysql.connector
# 注意把password设为你的root口令:
>>> conn = mysql.connector.connect(user='root', password='password', database='test')
>>> cursor = conn.cursor()
# 创建user表:
>>> cursor.execute('create table user (id varchar(20) primary key, name varchar(20))')
# 插入一行记录，注意MySQL的占位符是%s:
>>> cursor.execute('insert into user (id, name) values (%s, %s)', ['1', 'Michael'])
>>> cursor.rowcount
1
# 提交事务:
>>> conn.commit()
>>> cursor.close()
# 运行查询:
>>> cursor = conn.cursor()
>>> cursor.execute('select * from user where id = %s', ('1',))
>>> values = cursor.fetchall()
>>> values
[('1', 'Michael')]
# 关闭Cursor和Connection:
>>> cursor.close()
True
>>> conn.close()

import os

print('Process (%s) start...' % os.getpid())
# Only works on Unix/Linux/Mac:
pid = os.fork()
if pid == 0:
    print('I am child process (%s) and my parent is %s.' % (os.getpid(), os.getppid()))
else:
    print('I (%s) just created a child process (%s).' % (os.getpid(), pid))

from multiprocessing import Process
import os

# 子进程要执行的代码
def run_proc(name):
    print('Run child process %s (%s)...' % (name, os.getpid()))

if __name__=='__main__':
    print('Parent process %s.' % os.getpid())
    p = Process(target=run_proc, args=('test',))
    print('Child process will start.')
    p.start()
    p.join()
    print('Child process end.')

from multiprocessing import Pool
import os, time, random

def long_time_task(name):
    print('Run task %s (%s)...' % (name, os.getpid()))
    start = time.time()
    time.sleep(random.random() * 3)
    end = time.time()
    print('Task %s runs %0.2f seconds.' % (name, (end - start)))

if __name__=='__main__':
    print('Parent process %s.' % os.getpid())
    p = Pool(4)
    for i in range(5):
        p.apply_async(long_time_task, args=(i,))
    print('Waiting for all subprocesses done...')
    p.close()
    p.join()
    print('All subprocesses done.')

from peewee import *
import datetime
from playhouse.sqlite_ext import SqliteExtDatabase

db = MySQLDatabase(host='localhost', user='playground', passwd='playground', database='playground')
# db = SqliteExtDatabase('my_database.db')

class BaseModel(Model):
    class Meta:
        database = db

# 用户表
class User(BaseModel):
    username = CharField(unique=True)

# Twitter表
class Tweet(BaseModel):
    user = ForeignKeyField(User, related_name='tweets')
    message = TextField()
    created_date = DateTimeField(default=datetime.datetime.now)
    is_published = BooleanField(default=True)

def create_table():
    db.connect()
    db.create_tables([User, Tweet])

charlie = User.create(username='charlie')

huey = User(username='huey')
huey.save()

# 不需要设置 `is_published` 或 `created_date`，保存时会自动使用模型中指定的默认值
Tweet.create(user=charlie, message='My first tweet')

user = User.get(User.id == 1)

user = User.get(User.username == 'charlie')

for user in User.select():
    print(user.username)

Tweet.select().where(Tweet.user == user, Tweet.is_published == True)

usernames = ['charlie', 'huey', 'mickey']
users = User.select().where(User.username << usernames)

tweets = (Tweet
          .select()
          .join(User)
          .where(User.username << usernames))

Tweet.select().where(Tweet.id > 50).count()

tweets_today = (Tweet
                .select()
                .where(
    (Tweet.created_date >= datetime.date.today()) &
    (Tweet.is_published == True))
                .count())

User.select().order_by(User.username).paginate(3, 20)
Tweet.select().join(User).order_by(User.username, Tweet.created_date.desc())

tweet_ct = fn.Count(Tweet.id)
users = (User
         .select(User, tweet_ct.alias('ct'))
         .join(Tweet, JOIN.LEFT_OUTER)
         .group_by(User)
         .order_by(tweet_ct.desc()))

User.update(username='foo').where(User.id == 2).execute()

user = User.get(User.id == 1)
user.username='bar'
user.save()

Tweet.delete().where(id==1).execute()

user = User.get(User.id == 8)
user.delete_instance()

su: cannot set user id: Resource temporarily unavailable

cat /proc/sys/kernel/threads-max
254529

ps -u foobar -L | wc -l
1045

cat /etc/security/limits.conf

*    soft    nofile    655360
*    hard    nofile    655360
*    soft    noproc    655360
*    hard    noproc    655360
*    soft    core      0
*    hard    core      0

cat /etc/profile
cat /foobar/.bash_profile

tail -f /var/log/secure
blablabla...

Mar 30 12:08:02 localhost crond[29226]: pam_limits(crond:session): unknown limit item 'noproc'

blablabla...

vi /etc/security/limits.conf

*    soft    noproc    655360
*    hard    noproc    655360

*    soft    nproc    655360
*    hard    nproc    655360

Mar 30 12:10:25 localhost su: pam_unix(su-l:session): session opened for user foobar by monitor(uid=0)
Mar 30 12:10:25 localhost su: pam_unix(su-l:session): session closed for user foobar

cat /etc/security/limits.d/90-nproc.conf
*          soft    nproc     1024
root       soft    nproc     unlimited

vi /etc/security/limits.d/90-nproc.conf
*          soft    nproc     10240
root       soft    nproc     unlimited