Python Tutorial

Introduction Python Features Python Applications System requirements for Python Python Installation Python Basics Python Variables Python Data Types Python IDE Python Keywords Python Operators Python Comments Python Pass Statement

Python Conditional Statements

Python if Statement Python elif Statement Python If-else statement Python Switch Case

Python Loops

Python for loop Python while loop Python Break Statement Python Continue Statement Python Goto Statement

Python Arrays

Python Array Python Matrix

Python Strings

Python Strings Python Regex

Python Built-in Data Structure

Python Lists Python Tuples Python Lists vs Tuples Python Dictionary Python Sets

Python Functions

Python Function Python min() function Python max() function Python User-define Functions Python Built-in Functions Anonymous/Lambda Function in Python

Python File Handling

Python File Handling Python Read CSV Python Write CSV Python Read Excel Python Write Excel Python Read Text File Python Write Text File Read JSON File in Python

Python Exception Handling

Python Exception Handling Python Errors and exceptions Python Assert

Python OOPs Concept

OOPs Concepts in Python Classes & Objects in Python Inheritance in Python Polymorphism in Python Python Encapsulation Python Constructor Static Variables in Python Abstraction in Python

Python Iterators

Iterators in Python Yield Statement In Python

Python Generators

Python Generator

Python Decorators

Python Decorator

Python Functions and Methods

Python Built-in Functions Python String Methods Python List Methods Python Dictionary Methods Python Tuple Methods Python Set Methods

Python Modules

Python Modules Python Datetime Module Python Calendar Module  

Python MySQL

Python MySQL Python MySQL Update Operation Python MySQL Delete Operation

Python MongoDB

Python MongoDB

Python Data Structure Implementation

Python Stack Python Queue Python Hash Table Python Graph

Python Advance Topics

Speech Recognition in Python Face Recognition in Python Python Rest API Python Command Line Arguments Python JSON Python Virtual Environment Type Casting in Python Collections in python Python Enumerate Python Debugger Python DefaultDict


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How to

How to convert integer to float in Python How to reverse a string in Python How to take input in Python How to install Python in Windows How to install Python in Ubuntu How to install PIP in Python How to call a function in Python How to download Python How to comment multiple lines in Python How to create a file in Python How to create a list in Python How to declare array in Python How to clear screen in Python How to convert string to list in Python How to take multiple inputs in Python How to write a program in Python How to compare two strings in Python How to create a dictionary in Python How to create an array in Python How to update Python How to compare two lists in Python How to concatenate two strings in Python How to print pattern in Python How to check data type in python How to slice a list in python How to implement classifiers in Python How To Print Colored Text in Python How to develop a game in python How to print in same line in python How to create a class in python How to find square root in python How to import numy in python How to import pandas in python How to uninstall python How to upgrade PIP in python How to append a string in python How to open a file in python


Python Sort List Sort Dictionary in Python Python sort() function Python Bubble Sort


Factorial Program in Python Prime Number Program in Python Fibonacci Series Program in Python Leap Year Program in Python Palindrome Program in Python Check Palindrome In Python Calculator Program in Python Armstrong Number Program in Python Python Program to add two numbers Anagram Program in Python Even Odd Program in Python GCD Program in Python Python Exit Program Python Program to check Leap Year Operator Overloading in Python Pointers in Python Python Not Equal Operator Raise Exception in Python Salary of Python Developers in India What is a Script in Python Singleton design pattern in python

Python Command line Arguments

Python Command line Arguments

The command-line argument is used to the change functionality of the program. It's an extra command the programmer can use while launching a program. These commands have many uses such as adding more features and specialties into the program, specify a particular document to launch, and unlocking some special abilities of a computer or system that is disabled for normal use.

For example, if we talk about Python itself then to install the package or to use the pip command we have to write the command in the command line itself or in the PowerShell.

How to Pass Command-line Arguments in Python?

We suggest you, use the terminal to pass the argument into the file to make it reach the program. To pass the value through the terminal, we right the code:

$ python arg1 arg2 ... argN

How to use the command line Arguments in python?

Python supports the command-line, which means the commands can be run on the command-line too as well as in any editor.

Just save the file with the extension ".py". To use the command-line argument in Python, we have numerous commands to pass the argument.

We have to use that command with the parameter or what we can say with the arguments. By using those files with all that package will help them in using the command line arguments. they all are  given below:

  1. fire 
  2. docopt
  3. argparse
  4. optparse

What is fire?

Fire is one of the preferred packages used in the command line argument because it automatically generates the command-line interfaces (CLIs). Other than this, the Fire package supports all the versions of Python. It is faster. you don't require to pass any argument in this. all are linked. But this package is not inbuilt you have to install it by using the code.

py -m pip install fire


 #imported the fire package
 import fire 
 #created a class named 
 class javatpoint(object):
     #created a method named print 
     #to print hello
     def print(self):
     #created a method named open_file 
     #to print file name
     def open_file(self, filename):
         print("File Opened: ",filename)
 #calling the javatpoint class using fire
 if __name__ == '__main__':


 python hello  
 python File Opened: filename.txt  


In this example, we first install the fire package use the above-given pip command (py -m pip install fire), after installation, we open the notepad or any editor and start writing the code.

First, we imported the fire package into the file using the import keyword. Then we created a class named javatpoint with the parameter object. In that class we created two methods the first method will print and other is open_file method prints the Hello. The open_file prints the file opened and the filename. In the next step, we check if the initial has the main function or not. if yes then it will call the javatpoint class.

What is docopt?

The docopt is one of the powerful packages of Python. It helps the programmer to define an interface for a common-line application and generate the parsing values and argument for the program. The docopt is a command-line interface description module. But this package is not inbuilt you have to install it by using the code.

py -m pip install docopt


 use ='''
 Usage:  [(<name1>|<name2>)] <name3>...  mov <name1> <name2>  (--h|--q) [<name1> -l]  --version
   -l, --all      List all.
   -q, --quit     exit.
   --version      Version 3.9.4 
   -h --help      Show this screen.
   --version      Show version.
   --speed =<kn>   Speed in knots [default: 10].
   --moored       Moored (anchored) mine.
   --drifting     Drifting mine.   
 #importing the docopt package
 from docopt import docopt
 #passing the argument
 #using the docopt function
 arg = docopt(use)
 #printing the argument


 Usage:  [(<name1>|<name2>)] <name3>...  mov <name1> <name2>  (--h|--q) [<name1> -l]  --version
   -l, --all      List all.
   -q, --quit     exit.
   --version      Version 3.9.4 
   -h --help      Show this screen.
   --version      Show version.
   --speed =<kn>   Speed in knots [default: 10].
   --moored       Moored (anchored) mine.
   --drifting     Drifting mine.    


In this example, we first install the docopt package use the above-given pip command (py -m pip install docopt), after installation, we open the notepad or any editor and start writing the code. First, we created a variable named use and declare its value as long text.

In this, we are parsing multiple lines in a single variable. Then, we imported the docopt method from the docopt package into the file using the import and from keyword. Then, we declare a variable named arg and declare it with the docopt function and pass the variable named use we created above. then, we simply print the arg variable.

What is argparse?

The argparse is a module used to work with the command line argument. That's why it is known as the command line parsing module.

The first module version was released in 2011. The argparse allows us to use the positional argument and customize the prefix characters. it also supports subcommands and the variable numbers of parameters for a single option. But this package is not inbuilt you have to install it by using the code.

py -m pip install argparse

To run file:

 #code use to run the file in terminal
 \desktop\sachin\JavaTpoint\dictionary>python –h 


 #importing the argparse module
 import argparse  
 #declaring the variable with 
 # the ArgumentParser method 
 # argparse module
 par = argparse.ArgumentParser()  
 # creating the variables using the add_argument method  
 par.add_argument("first_name", help = "first name")  
 par.add_argument("last_name ", help = "last name")  
 par.add_argument("operation", help = "operation")   


 usage: [-h] Java Tpoint operation
 positional arguments:
   Java        first number
   Tpoint        second number
   operation   operation
 optional arguments:
 -h, --help  show this help message and exit 


In this example, we first install the argparse package use the above-given pip command (py -m pip install argparse), after installation, we open the notepad or any editor and start writing the code.

First, import the module argparse using the import keyword. After this, we declared a variable with the argument parser method of the argparse module. then we use the add argument method of the argument parser method and the argparse module to add the arguments. we have taken the 3 arguments to add.

What is optparse?

The optparse module is used to make code writing easy. that results in easy writing the command-line tool.

As we are talking about the command-line argument, it's of course that the optparse is the command-line argument parsing module.

The optparse is the favorable option of the programmers because it makes it easy to handle the command-line argument. It provides the options and allows the dynamic data to be taken from the users, and also, it is the inbuilt module of python. It is capable of working with the lesser than the 2.7 version of python and also with the higher version of python.

To run file:

 #code use to run the file in terminal
 python -n 5 


 # import optparse module
 import optparse
 # created a function 
 #named table 
 def table(n, dest_cheak):
     for i in range(1,11):
         tab = i*n
         print ("The " + str(i)+ "th value of "+str(n)+" table is " + str(tab))
     return tab
 # define a function for 
 # adding options
 def Main():
     # create OptionParser object
     par = optparse.OptionParser()
     # adding the options
     par.add_option('-n', dest = 'num',
                       type = 'int', 
                       help = 'specify the n''th table number to output')
     par.add_option('-o', dest = 'out',
                       type = 'string', 
                       help = 'specify an output file (Optional)')
     par.add_option("-a", "--all", 
                       action = "store_true",
                       dest = "prin", 
                       default = False,
                       help = "print all numbers up to N")
     (options, args) = par.parse_args()
     if (options.num == None):
             print (par.usage)
             number = options.num
     # function calling
     result = table(number, options.prin)
 # Driver code
 if __name__ == '__main__':
   # function calling


 python -n 5
 The 1th value of 5 table is 5
 The 2th value of 5 table is 10
 The 3th value of 5 table is 15
 The 4th value of 5 table is 20
 The 5th value of 5 table is 25
 The 6th value of 5 table is 30
 The 7th value of 5 table is 35
 The 8th value of 5 table is 40
 The 9th value of 5 table is 45
 The 10th value of 5 table is 50 


Firstly we imported the optparse in the file by using the import keyword. Then we have created a function named table in that we are printing the table using for loop.

Then we created the function main and in that function, we created an object named par and declare it by the module optparse with its method OptionParser. Then we add the options for the number, string, and operations. This helps in allowing the dynamic data input. Then we check that the input that is an integer or not.

 If it's an integer then we pass the value to the table function to print the table. and the output is attached above. This is the basic example of the optparse.