Python processing command-line arguments

1. Save the command-line arguments in the list, note that argv[0] is the name of the program itself:

Import Sysprint (SYS.ARGV)                                                       print (sys.argv[1])

Python argv.py localhost 3306
[' argv.py ', ' localhost ', ' 3306 ']
localhost

2. Use Sys.stdin and fileinput to read the standard input and print the pipeline in the terminal-like shell

Import sys for line in      Sys.stdin:print (line,end= "")   

can be typed as a shell script, with standard input to the program

Python read_stdin.py </etc/passwd

Python read_stdin.py-

CAT/ETC/PASSWD |python read_stdin.py

Save standard input in a list

Import Sysdef get_content ():                                                         return Sys.stdin.readlines () print (Get_content ())

Python readlines_stdin.py <test/1.txt
[' hello\n ', ' world\n ']

3. Read standard input with Fileinput

#/usr/bin/env python#coding=utf-8                                                         Import fileinputfor line in Fileinput.input ():     print (line,end= "")

Python file_input1.py/etc/passwd

Python file_input1.py </etc/passwd

Python file_input1.py/etc/passwd/etc/my.cnf

Common methods of Fileinput:

#!/usr/bin/pythonfrom __future__ import print_functionimport fileinputfor line in Fileinput.input ():    meta = [ Fileinput.filename (), Fileinput.fileno (), Fileinput.filelineno (),            fileinput.isfirstline (), Fileinput.isstdin ( )]    print (*meta, end= "")
    Print ()    print (line, end= "")

4. Use Getpass to read the password:

Import Getpassuser=getpass.getuser () passwd=getpass.getpass (' You password: ')                              print (USER,PASSWD)

Can avoid entering the password to be seen

5. Parsing command-line arguments using Argparse

Agrparse ability to parse parameters from Sys.arg and automatically generate Help information

From __future__ import print_functionimport argparsedef _argparse ():        parser = Argparse. Argumentparser (description= "This is description")        parser.add_argument ('--host ', action= ' store ',                                dest= ' Server ', default= "localhost", help= ' connect to host ')        parser.add_argument ('-t ', action= ' store_true ',                                    Default=false, dest= ' Boolean_switch ', help= ' Set a switch to True ')        return Parser.parse_args () def main ():       Parser = _argparse ()       print (parser) print (       ' host = ', Parser.server)       print (' boolean_switch= ', Parser.boolean_switch) If __name__ = = ' __main__ ':    Main ()

Format: rgumentparser.add_argument (name or flags ...) [, Action] [, Nargs] [, Const] [, Default] [, type] [, Choices] [, Required] [, help] [, Metavar] [, dest])

Name: Names of parameters

Action: Actions When a parameter is encountered

Nargs: Number of parameters

Dest: The name of the parsed argument

Type: Types of parameters

6. Use Click to create a command-line resolution

Click Compare Argparse more fast and easy

PIP Inst Click

Import Click@click.command () @click. Option ('--count ', default=1, help= ' number of greetings. ') @click. Option ('--name ', prompt= ' Your name ',              help= ' the person to greet. ') def hello (count, name): "" "Simple Program,"    greets name for a total of count times.    "" " For x in range (count):        click.echo (' Hello%s! '% name) if __name__ = = ' __main__ ':    Hello ()

Commond making a function a command-line interface

Option: Add command-line Options

Echo: Output result

Prompt: If the name parameter is not specified, enter in interactive mode

　

You can also enter the default editor like FC in Linux

Import clickmessage = Click.edit () print (message,end= "")

　　

Python processing command-line arguments