Python standard module that can be used on the command line
Launch a python module from the command line
$ python --help
usage: python [option] ... [-c cmd | -m mod | file | -] [arg] ...
...
-m mod : run library module as a script (terminates option list)
...
-m mod : run library module as a script (terminates option list)
If you start python with the -m option, it will search for the module in $ PYTHONPATH and execute it.
Just by advocating Battery Included, you can use a wide range of functions without writing code.
Even if you're not interested in the Python language itself, it's helpful to remember it when working with the shell.
However, it seems that there are many things that are not well documented, so I will introduce what I know.
Introduction of modules that can be used
Both can be used with python2 series (which is included as standard for OSX / Linux). No need to install special packages.
json.tool
Receives JSON data from standard input, formats it and displays it.
$ echo '{"spam": ["ham", "egg"]}' | python -m json.tool
{
"spam": [
"ham",
"egg"
]
}
You can't use jq or jsonlint without installing it, but python can be used in many environments.
The weak point is that the indent is fixed at 4 (others are usually 2), so it's good to pipe to sed -e's / / / g'.
SimpleHTTPServer
Publish under the current directory via HTTP.
$ python -m SimpleHTTPServer 8080
Serving HTTP on 0.0.0.0 port 8080 ...
If you access http: // localhost: 8080 in this state, you can see the file list.
It can be used for debugging web applications and checking HTML files. With no arguments, port 8000 is used by default.
CGIHTTPServer
Almost the same as SimpleHTTPServer, but with CGI enabled.
$ python -m CGIHTTPServer
Serving HTTP on 0.0.0.0 port 8000 ...
Very useful for publishing small CGI scripts on your LAN.
smtpd
Set up an SMTP proxy server locally.
It can be used in combination with smtplib described later.
$ sudo python -m smtpd -d -n localhost:25
smtplib
Send an email to localhost.
Prompts will appear in the order of From, To, Body, so write an email from standard input.
$ python -m smtplib
ftplib
Become an ftp client.
$ python -m ftplib ftp://localhost
It's a degraded copy of the ftp command, but it's possible that there is no ftp and there is a python.
telnetlib
Become a telnet client.
$ python -m telnetlib towel.blinkenlights.nl
You can watch the AA version of the famous Star Wars Episode 4.
poplib
Become a pop3 mail client.
$ python -m poplib localhost user password
htmllib
Become a text browser. Since you cannot refer to the URL directly, you need to download it locally in advance.
$ python -m htmllib index.html
It's not a great substitute for w3m or lynx, such as not interpreting inline javascript.
If you are forced to think about how to use it, it will be a watershed between parsing non-well-formatted HTML with htmllib or bringing out BeautifulSoup (if this command fails, it is HTML that cannot be parsed by Python standard, so BeautifulSoup You can use to determine that it should be analyzed).
xmllib
Parse XML.
$ python -m xmllib egg.xml
xml: encoding = ISO-8859-1 standalone = None
data: '\n'
...
It doesn't seem to be usable by itself ... It may be used a little if combined with ʻawk`. But it's better to write a script than to do that.
filecmp
Take the difference between the two directories.
python -m filecmp dir1/ dir2/
diff dir1 dir2
Only in dir1 : ['foo.txt']
Only in dir2 : ['bar.txt']
Differing files : ['baz.txt']
Recursively traverse directories with the -r option (default is only one level).
You can see the file name and whether it has been changed, but note that the contents are not displayed.
gzip
GZIP compression / decompression tool.
$ python -m gzip baz.tar # compress
$ python -m gzip -d baz.tar.gz # decompress
Slightly less functional than the zipfile described below. I don't even help.
You can't expand tar, so you may not use it.
zipfile
ZIP compression / decompression tool.
$ python -m zipfile -c foo.zip bar.txt baz.png
List with the -l option, test with the -t option, expand with the -e option, and compress with the -c option.
You can do most of the operations with the zip command, but it is subtle if you have a chance to use it (in an environment where this module can be used, the zip command is likely to be used as well).
mimetype
Takes a file name as an argument and returns the MIMETYPE of that file.
$ python -m mimetype ham.png
type: image/png encoding: None
Since it is judged from the file name, it works even if the file itself does not exist.
Is it almost equivalent to the --mimetype option of the file command?
base64
Base64 encode / decode standard input and display it on standard output.
$ echo 'python' | python -m base64
cHl0aG9uCg==
$ echo 'cHl0aG9uCg==' | python -m base64 -d
python
Almost equivalent to the ʻopenssl base64command. There seems to be a decent environment withpython without ʻopenssl.
uu
Encode / decode standard input with uuencode and display it on standard output.
$ python -m uu < baz.png
There are few opportunities to use it compared to base64.
mimify
Encode / decode the standard input into a format that can be handled by e-mail and display it on the standard output. Similar to base64, but with a mail header.
$ python -m mimify -e foo.jpg # encode
$ python -m mimify -d bar.eml # decode
It is recommended to redirect to a file as control characters can corrupt the terminal.
quopri
Encode / decode standard input with Quoted-printable and display it on standard output.
$ python -m quopri < quux.png
Base64 is the de facto standard for these binary <=> ascii conversion codecs, and there are few opportunities to use them.
timeit
Measure the execution time of a piece of Python code. It seems to be more precise than the POSIX time command.
It is quite smart, such as automatically determining the number of loops so that the error is small.
$ python -m timeit 'pow(2, 10000)'
10000 loops, best of 3: 25 usec per loop
There are many options.
See python -m timeit -h for more information.
profile
Measure the profile of a Python script.
$ python -m profile ham.py
473 function calls in 0.009 seconds
Ordered by: standard name
ncalls tottime percall cumtime percall filename:lineno(function)
1 0.000 0.000 0.000 0.000 :0(range)
1 0.006 0.006 0.006 0.006 :0(setprofile)
...
Good for finding bottlenecks when tuning scripts.
modulefinder
Recursively search for the module you are importing.
$ python -m modulefinder foo.py
Name File
---- ----
m __main__ foo.py
m array
m re /usr/lib/python2.7/re.py
You can use it when you are addicted to a dependency ... Isn't it?
unittest
A test runner for Python's standardized test library ʻunittest`. Since it is described in detail in Reference, the explanation is omitted.
It's good to remember the idiom of python -m unittest discover -v.
doctest
This is also a test runner for Python's standardized test library doctest.
See Reference.
After all it is OK if you only remember python -m doctest -v foo.py.
Personally, I think it's a very Python-like module.
site
Display information such as module loading destination, sys.path.
$ python -m site
sys.path = [
'/usr/lib/python2.7',
'/usr/lib/python2.7/plat-x86_64-linux-gnu',
...
You can list environment variables related to Python, so it seems to be useful.
platform
Display OS information.
$ python -m platform
Linux-3.13.0-48-generic-x86_64-with-Ubuntu-14.04-trusty
The output information is like adding ʻuname -aand (in Linux)cat / etc / issue`.
It is easy to use because it is normalized by hyphen delimiter.
shlex
Become a shell lexical analyzer. Cut out tokens using Bourne shell style grammar.
$ echo 'spam ham egg' | python -m shlex
Token: 'spam'
Token: 'ham'
Token: 'egg'
The purpose is unknown, but there seems to be no similar command.
locale
Display locale settings.
$ python -m locale
Locale aliasing:
Locale defaults as determined by getdefaultlocale()
-----------------------------------------------------------------
Language: ja_JP
Encoding: UTF-8
Locale settings on startup:
-----------------------------------------------------------------
LC_NUMERIC ...
Language: (undefined)
Encoding: (undefined)
...
The display is easy to read (redundant), which is almost the same as the locale command.
webbrowser
A module that just opens a browser from the command line.
$ python -m webbrowser -n http://qiita.com
Open a window with the -n option and a new tab with the -t option.
It's sober, but there aren't many similar commands, so it might be useful if you have a messenger.
The browser to open is automatically selected as specified by the system and cannot be changed.
tabnanny
Check the indentation of the Python script, correct any ambiguity, and rewrite.
$ python -m tabnanny my_script.py
The directory can also be taken as an argument, but be careful as it will recursively overwrite the files inside.
compileall
Compile a Python script.
python -m compileall my_project/
Recursively search directories and compile .py files into .pyc.
Since it has a decompiler, it cannot be used for obfuscation,
Usually, the performance improvement is not so big, so I don't have much chance to use it.
Click here for Reference.
dis
Python disassembler. Analyze the code in the * .py script.
$ python -m dis /usr/lib/python2.7/abc.py
4 0 LOAD_CONST 0 ('Abstract Base Classes (ABCs) according to PEP 3119.')
3 STORE_NAME 0 (__doc__)
6 6 LOAD_CONST 1 (-1)
9 LOAD_CONST 2 (None)
12 IMPORT_NAME 1 (types)
15 STORE_NAME 1 (types)
8 18 LOAD_CONST 1 (-1)
21 LOAD_CONST 3 (('WeakSet',))
See Reference for a list of instructions.
bonus
code
Open the interpreter. Equivalent to the python command with no arguments.
$ python -m code
Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
trace
Trace Python function calls.
Reference describes how to use it, but honestly, I feel that pdb is enough.
pdb
Start Python's interactive debugger pdb.
See Reference for details.
It is usually provided as a pdb command, so you don't have to call it as a module.
pydoc
This is also the familiar pydoc command, but it can also be started as a module.
turtle
Demonstration of the standard GUI module Tkinter.
Although it is attached as standard, please note that it is not included depending on the environment such as OSX.
$ python -m turtle
encodings.rot_13
Encrypt the standard input with rot13 and display it on the standard output.
$ echo 'hamegg' | python -m encodings.rot_13
unzrtt
Originally a story module. I don't usually use it, but it's interesting that rot13 is included in the standard library.
antigravity
$ python -m antigravity
Neta module part 2. I will not explain it.
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