Python 冷兵器合集

python中自带了一些命令行工具，可以用来快速处理一些工作。我把这些命令行工具称之为 冷兵器 ，没有趁手的工具时候就可以顶替使用。这些工具都是python的标准模块，具有 main 函数，可以直接使用 python -m 命令执行，多数可以使用 -h/--help查看帮助。

1. http 服务

启动一个http的静态文件服务

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# python -m http.server
Serving HTTP on :: port 8000 (http://[::]:8000/) ...

2. json 格式化

格式化json数据

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# echo '{"amount":3.4}' | python -m json.tool
{
    "amount": 3.4
}

3. 可视化编辑器和shell

idlelib模块基于tkinter，可以作为编辑器和shell使用。文件编辑器效果。

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python -m idlelib myapp/example.py

gui-ide

shell效果

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python -m idlelib

gui-shell

4. python 应用程序打包

构建myapp目录如下:

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├── myapp
│   ├── example.py
│   └── hello.py

代码分别如下:

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# example.py

import hello

def main():
   print('Hello World')
   hello.say_hello("python")
   
if __name__=='__main__':
   main()

# hello.py

def say_hello(name):
	print("hello",name)

将整个myapp打包成应用程序，命令执行后会生成一个名叫 myapp.pyz 应用程序。

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python -m zipapp myapp -m "example:main"

使用python直接运行应用程序

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# python myapp.pyz
Hello World
hello python

5. ROT13 加密

rot13（rotate by 13 places）是一种简易的替换式密码，是凯撒密码的变种。rot13将原文偏移13位形成密文，因为英文总共26位，所以密文再偏移13位后会回到原文。公式: rot13(rot13(xxx))=xxx。

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# echo "xxx" | python -m encodings.rot_13
Tvir zr n fgne

作为一个小彩蛋，欢迎大家动手破译一下xxx的值

6. base64 编码

对一个字符串进行base64编码

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# echo "haha" | python -m base64
aGFoYQo=
# echo "aGFoYQo=" | python -m base64 -d
haha

base64还支持对文件编码。编写测试代码

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# sample.py

def main():
   print('Hello World👌')
   
if __name__=='__main__':
   main()

将代码编译成base64字符串

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# python -m base64 sample.py
CmRlZiBtYWluKCk6CiAgIHByaW50KCdIZWxsbyBXb3JsZPCfkYwnKQogICAKaWYgX19uYW1lX189
PSdfX21haW5fXyc6CiAgIG1haW4oKQo=

执行编译后的代码

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# echo "CmRlZiBtYWluKCk6CiAgIHByaW50KCdIZWxsbyBXb3JsZPCfkYwnKQogICAKaWYgX19uYW1lX189
PSdfX21haW5fXyc6CiAgIG1haW4oKQo=" | python -m base64 -d | python
Hello World👌

类似的可以使用uu(Unix-to-Unix encoding)编码代码:

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# python -m uu sample.py
begin 644 sample.py
M"F1E9B!M86EN*"DZ"B @('!R:6YT*"=(96QL;R!7;W)L9/"?D8PG*0H@(" *
C:68@7U]N86UE7U\]/2=?7VUA:6Y?7R<Z"B @(&UA:6XH*0H

end

使用quopri(Encode and decode MIME quoted-printable data)编码代码:

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# python -m quopri -t sample.py

def=20main():
=20=20=20print('Hello=20World=F0=9F=91=8C')
=20=20=20
if=20__name__=3D=3D'__main__':
=20=20=20main()

7. mime 识别

识别文件或者url的mime类型

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# python -m mimetypes https://docs.python.org/3/library/mimetypes.html
type: text/html encoding: None  # html
# python -m mimetypes https://www.google.com/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png
type: image/png encoding: None  # png
# python -m mimetypes sample.py
type: text/x-python encoding: None  # python文件
# python -m mimetypes sample.py.gz
type: text/x-python encoding: gzip  # python文件，gzip压缩

8. 查看python环境信息

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python -m sysconfig
Platform: "macosx-10.9-x86_64"
Python version: "3.8"
Current installation scheme: "posix_prefix"

Paths:
	data = "/Users/yoo/work/yuanmahui/python/.venv"
	include = "/Library/Frameworks/Python.framework/Versions/3.8/include/python3.8"
	...

Variables:
    ...
	PYTHON = "python"
	PYTHONFRAMEWORK = "Python"
	PYTHONFRAMEWORKDIR = "Python.framework"
	PYTHONFRAMEWORKINSTALLDIR = "/Library/Frameworks/Python.framework"
	...

也可以使用下面命令查看系统路径

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# python -m site
sys.path = [
    '/Users/yoo/work/yuanmahui/python/python-tools',
    '/Library/Frameworks/Python.framework/Versions/3.8/lib/python38.zip',
    '/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8',
    '/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/lib-dynload',
    '/Users/yoo/work/yuanmahui/python/.venv/lib/python3.8/site-packages',
]
USER_BASE: '/Users/yoo/Library/Python/3.8' (exists)
USER_SITE: '/Users/yoo/Library/Python/3.8/lib/python/site-packages' (exists)
ENABLE_USER_SITE: False

9. 编译脚本

compileall可以编译python脚本。myapp目录有2个py脚本

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# ll myapp
total 16
-rw-r--r--  1 yoo  staff   118B  2 26 23:03 example.py
-rw-r--r--  1 yoo  staff    43B  2 26 23:03 hello.py

编译脚本

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# python -m compileall myapp
Listing 'myapp'...
Compiling 'myapp/example.py'...
Compiling 'myapp/hello.py'...

查看编译结果

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tree myapp -L 3
myapp
├── __pycache__
│   ├── example.cpython-38.pyc
│   └── hello.cpython-38.pyc
├── example.py
└── hello.py

1 directory, 4 files

10. 压缩和解压

创建和解压tar包

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# python -m tarfile -c myapp.tar myapp  # 创建myapp.tar 压缩包
# python -m tarfile -e myapp.tar myapp2 # 解压myapp.tar 到 myapp2目录

使用gzip压缩文件

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# python -m gizp sample.py
# python -m gzip -d sample.py.gz

使用zip打包文件

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# python -m zipfile -c myapp.zip myapp
# python -m zipfile -e myapp.zip myapp2

注意: zipfile和zipapp不一样, 后则是生成一个可以执行的app

11. telnet 工具

没有telnet工具的python容器中可以这样:

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# python -m telnetlib -d redis 6379  # 连接redis
monitor
Telnet(redis,6379): send b'monitor\n'
Telnet(redis,6379): recv b'-NOAUTH Authentication required.\r\n'
-NOAUTH Authentication required.

还有 nntplib && ftplib 两个工具，应该很少使用，就不介绍了

12. 性能和调试工具

自带的timeit可以测试脚本的性能数据

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# python -m timeit '"-".join([str(n) for n in range(100) if n%2 == 0])'  # 取模求偶数
20000 loops, best of 5: 12.5 usec per loop
# python -m timeit '"-".join([str(n) for n in range(0,100,2)])'  # 步进
50000 loops, best of 5: 8.85 usec per loop
# python -m timeit '"-".join([str(n) for n in range(100) if n&1 == 0])'  # 位运算判断奇偶
20000 loops, best of 5: 14.3 usec per loop

不科学1: 位运算竟然比取模慢？

如果不是一个字符串而是一个脚本：

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def test_normal():
	tmp = ""
	for x in range(100):
		if x % 2 == 0:
			if tmp:
				tmp = tmp+"-"+str(x)
			else:
				tmp = str(x)
	return tmp

if __name__ == '__main__':
	print(test_normal())

可以下面方式变通使用

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# python -m base64 test_string_join.py | python -m base64 -d | python -m timeit
50000000 loops, best of 5: 5.33 nsec per loop

不科学2: 50000000循环只需要5.33纳秒，而之前的用例20000循环需要12.5微秒

标准库中还有 pdb && profile && pstats 使用比较复杂，暂时就不介绍

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pypy3 -m timeit '[{} for n in range(1000)]'
WARNING: timeit is a very unreliable tool. use pyperf or something else for real measurements
pypy3 -m pip install pyperf
pypy3 -m pyperf timeit '[{} for n in range(1000)]'
------------------------------------------------------------
100000 loops, average of 7: 7.3 +- 0.107 usec per loop (using standard deviation)

[tywork@liujunhong_szfsfz_work1 config]$ pypy3 -m pyperf timeit '[{} for n in range(1000)]'
........
Mean +- std dev: 8.42 us +- 0.25 us
[tywork@liujunhong_szfsfz_work1 config]$
[tywork@liujunhong_szfsfz_work1 config]$
[tywork@liujunhong_szfsfz_work1 config]$
[tywork@liujunhong_szfsfz_work1 config]$ pypy3 -m pyperf timeit '[dict() for n in range(1000)]'
.........
Mean +- std dev: 29.6 us +- 1.1 us

13. pydoc

本地服务方式查看python代码文档

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# python -m pydoc -p 8080  # 启动一个web服务
Server ready at http://localhost:8080/
Server commands: [b]rowser, [q]uit
server> b

文档效果如图 requests-doc

14. test

执行python自带的测试用例，查看系统支持那些特性

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# python -m test.regrtest -u cpu
== CPython 2.7.16 (default, Jun 5 2020, 22:59:21) [GCC 4.2.1 Compatible Apple LLVM 11.0.3 (clang-1103.0.29.20) (-macos10.15-objc-
==   Darwin-19.6.0-x86_64-i386-64bit little-endian
==   /private/var/folders/mv/3vgd3mdx2453clfcst7qlm280000gn/T/test_python_13470
== CPU count: 12
Run tests sequentially
0:00:00 load avg: 2.53 [  1/404] test_grammar
...
= Tests result: FAILURE ==

363 tests OK.

5 tests failed:
    test_import test_posix test_py_compile test_rlcompleter
    test_scriptpackages

36 tests skipped:
    test_al test_bsddb test_bsddb3 test_cd test_cl test_codecmaps_cn
    test_codecmaps_hk test_codecmaps_jp test_codecmaps_kr
    test_codecmaps_tw test_curses test_epoll test_gdb test_gdbm
    test_gl test_imgfile test_largefile test_linuxaudiodev test_msilib
    test_ossaudiodev test_poll test_py3kwarn test_smtpnet
    test_socketserver test_spwd test_startfile test_sunaudiodev
    test_timeout test_tk test_tools test_ttk_guionly test_urllib2net
    test_urllibnet test_winreg test_winsound test_zipfile64
2 skips unexpected on darwin:
    test_spwd test_tools

Total duration: 5 min 23 sec
Tests result: FAILURE

从测试用例，可以看到osx支持fork，不支持epoll和poll。

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0:00:47 load avg: 1.79 [138/404] test_fork1
...
0:00:39 load avg: 1.59 [125/404] test_epoll
test_epoll skipped -- test works only on Linux 2.6
...
0:02:42 load avg: 2.41 [257/404/1] test_poll
test_poll skipped -- select.poll not defined -- skipping test_poll
0:02:42 load avg: 2.41 [258/404/1] test_popen -- test_poll skipped

参考链接

PEP441–Improving Python ZIP Application Support https://www.python.org/dev/peps/pep-0441/
ROT13 https://zh.wikipedia.org/wiki/ROT13

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