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- Herausgeber: Packt Publishing
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Leverage the features and libraries of Python to administrate your environment efficiently.
Key Features
- Learn how to solve problems of system administrators and automate routine activities
- Learn to handle regular expressions, network administration
- Building GUI, web-scraping and database administration including data analytics
Book Description
Python has evolved over time and extended its features in relation to every possible IT operation. Python is simple to learn, yet has powerful libraries that can be used to build powerful Python scripts for solving real-world problems and automating administrators' routine activities. The objective of this book is to walk through a series of projects that will teach readers Python scripting with each project.
This book will initially cover Python installation and quickly revise basic to advanced programming fundamentals. The book will then focus on the development process as a whole, from setup to planning to building different tools. It will include IT administrators' routine activities (text processing, regular expressions, file archiving, and encryption), network administration (socket programming, email handling, the remote controlling of devices using telnet/ssh, and protocols such as SNMP/DHCP), building graphical user interface, working with websites (Apache log file processing, SOAP and REST APIs communication, and web scraping), and database administration (MySQL and similar database data administration, data analytics, and reporting).
By the end of this book, you will be able to use the latest features of Python and be able to build powerful tools that will solve challenging, real-world tasks
What you will learn
- Understand how to install Python and debug Python scripts
- Understand and write scripts for automating testing and routine administrative activities
- Understand how to write scripts for text processing, encryption, decryption, and archiving
- Handle files, such as pdf, excel, csv, and txt files, and generate reports
- Write scripts for remote network administration, including handling emails
- Build interactive tools using a graphical user interface
- Handle Apache log files, SOAP and REST APIs communication
- Automate database administration and perform statistical analysis
Who this book is for
This book would be ideal for users with some basic understanding of Python programming and who are interested in scaling their programming skills to command line scripting and system administration.
Prior knowledge of Python would be necessary.
Das E-Book können Sie in Legimi-Apps oder einer beliebigen App lesen, die das folgende Format unterstützen:
Seitenzahl: 306
Veröffentlichungsjahr: 2019
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Mastering Python Scripting for System Administrators
Copyright © 2019 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing or its dealers and distributors, will be held liable for any damages caused or alleged to have been caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
Commissioning Editor: Vijin BorichaAcquisition Editor: Shrilekha InaniContent Development Editor: Sharon RajTechnical Editor: Prashant ChaudhariCopy Editor:Safis EditingProject Coordinator: Drashti PanchalProofreader: Safis EditingIndexer: Rekha NairGraphics: Tom ScariaProduction Coordinator: Jyoti Chauhan
First published: January 2019
Production reference: 1240119
Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK.
ISBN 978-1-78913-322-6
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Contributors
About the author
Ganesh Sanjiv Naik is an author, consultant, and corporate trainer in the fields of AI, data science, machine learning, the Internet of Things (IoT), and embedded Linux in relation to product development. He has more than 20 years of professional experience in information technology. Ganesh has a passion and a deep desire for teaching. He has trained 2,000+ engineers in Linux and Android product development. He has worked as a corporate trainer for the ISRO, Intel, GE, Samsung, Motorola, Penang Skill Development Center (Malaysia), and various companies in Singapore, Malaysia, and India. He has started a company called Levana Technologies, which works in AI, machine learning, and data science, providing training, projects, and consultancy activities.
About the reviewers
Yogendra Sharma is a developer with experience in the architecture, design, and development of scalable and distributed applications, with a core interest in microservices and Spring. He is currently working as an IoT and cloud architect at Intelizign Engineering Services Pvt, Pune. He also has hands-on experience in technologies such as AWS Cloud, IoT, Python, J2SE, J2EE, Node.js, Angular, MongoDB, and Docker. He constantly explores technical novelties, and he is open-minded and eager to learn about new technologies and frameworks. He has reviewed several books and video courses published by Packt Publishing.
Abhijeet Mote has a master's degree in computer application (MCA) from University of Mumbai. He is an open source evangelist and works as a senior software engineer. He has worked in multiple domains, including education, media, and IoT. His hobbies involve work on open source projects, and he loves to give back to the open source community by spreading knowledge of Python and other open source stacks. He conducts training sessions for students, teachers, and enthusiastic developers, and he mentors students for their final year projects. He has been invited to conferences, such as FOSSASIA 2018, and PyGotham, for his contribution in teaching open source technology to enthusiastic developers and underrepresented groups.
Packt is searching for authors like you
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Table of Contents
Title Page
Copyright and Credits
Mastering Python Scripting for System Administrators
Dedication
About Packt
Why subscribe?
Packt.com
Contributors
About the author
About the reviewers
Packt is searching for authors like you
Preface
Who this book is for
What this book covers
To get the most out of this book
Download the example code files
Conventions used
Get in touch
Reviews
Python Scripting Overview
Technical requirements
Why Python?
Python syntax compared to other programming languages
Python installation
Installation on the Linux platform
Installation on the Windows platform
Installing and using pip to install packages
Installation on Mac
Installing Jupyter notebook
Installing and using the virtual environment
Installing Geany and PyCharm
Python interpreter
The difference between Python and Bash scripting
Starting the interactive console
Writing scripts with the Python interactive console
Multiple lines
Importing modules through the Python interpreter
Exiting the Python console
The keyboard shortcut
Using the quit() or exit() functions
Indentation and tabs
Variables
Creating and assigning values to variables
Numbers
Number type conversion
Strings
Concatenation (+) and repetition (*)
String slicing
Accessing values in strings
Updating strings
Escape characters
Special string operators
%  string formatting operator
Triple quotes in Python
Strings are immutable
Understanding lists
Accessing values in lists
Updating lists
Deleting list elements
Basic list operations
List operations
Indexing, slicing, and matrices
Tuples
Accessing values in tuples
Updating tuples
Deleting tuple elements
Basic tuple operations
Indexing, slicing, and matrices
max() and min()
Sets
Dictionaries
Parsing command-line arguments
Command-line arguments in Python
Sys.argv
Decision making
Python if statement syntax
Python if...else statement syntax
Python if...elif...else statement
Loops
for loop
The range() function
while loop
Iterators
Generators
How to create a generator in Python?
Functions
The return statement
Lambda functions
Modules
Importing modules
Summary
Questions
Further reading
Debugging and Profiling Python Scripts
What is debugging?
Python debugging techniques
Error handling (exception handling)
Debuggers tools
The pdb debugger
Within an interpreter
From a command line
Within a Python script
Debugging basic program crashes
Profiling and timing programs
The cProfile module
timeit
Making programs run faster
Summary
Questions
Further reading
Unit Testing - Introduction to the Unit Testing Framework
What is unittest?
Creating unit tests
Methods used in unit testing
Summary
Questions
Further reading
Automating Regular Administrative Activities
Accepting input by redirection, pipe, and input files
Input by redirection
Input by pipe
Input by input file
Handling passwords at runtime in scripts
Executing external commands and getting their output
Capturing output using the subprocess module
Prompting for passwords during runtime and validation
Reading configuration files
Adding logging and warning code to scripts
Generating warnings
Putting limits on CPU and memory usage
Launching webbrowser
Using the os module for handling directory and files
Creating and deleting the directory
Examining the content of a filesystem
Making backups (with rsync)
Summary
Questions
Further reading
Handling Files, Directories, and Data
Using the os module to work with directories
Get the working directory
Changing the directory
Listing files and directories
Renaming a directory
Copying, moving, renaming, and deleting data
Copying the data
Moving the data
Renaming data
Deleting data
Working with paths
Comparing data
Merging data
Pattern matching files and directories
Metadata: data about data
Compressing and restoring
Using the tarfile module to create TAR archives
Using a tarfile module to examine the contents of TAR files
Summary
Questions
Further reading
File Archiving, Encrypting, and Decrypting
Creating and unpacking archives
Creating archives
Unpacking archives
Tar archives
ZIP creation
File encryption and decryption
Summary
Questions
Further reading
Text Processing and Regular Expressions
Text wrapping
The wrap() function
The fill() function
The dedent() function
The indent() function
The shorten() function
Regular expressions
The match() function
The search() function
The findall() function
The sub() function
Unicode strings
Unicode code point
Encoding
Decoding
Avoiding UnicodeDecodeError
Summary
Questions
Further reading
Documentation and Reporting
Standard input and output
Information formatting
Sending email
Summary
Questions
Further reading
Working with Various Files
Working with PDF files
Reading a PDF document and getting the number of pages
Extracting text
Rotating PDF pages
Working with Excel files
Using the xlrd module
Reading an Excel file
Extracting the names of columns
Using pandas 
Reading an Excel file
Reading specific columns in an Excel file
Using openpyxl
Creating a new Excel file
Appending values
Reading multiple cells
Working with CSV files
Reading a CSV file
Writing into a CSV file
Working with txt files
The open() function
File opening
The close() function
Writing a text file
Reading a text file
Summary
Questions
Further reading
Basic Networking - Socket Programming
Sockets
The http package
The http.client module
The http.server module
The ftplib module
Downloading files
Getting a welcome message using getwelcome():
Sending commands to the server using the sendcmd() function
The urllib package
Python urllib response headers
Summary
Questions
Further reading
Handling Emails Using Python Scripting
Email message format
Adding HTML and multimedia content
POP3 and IMAP servers
Receiving email using the poplib library
Receiving email using the imaplib library
Summary
Questions
Remote Monitoring of Hosts Over Telnet and SSH
The telnetlib() module
SSH
The subprocess.Popen() module
SSH using fabric module
SSH using the Paramiko library
SSH using the Netmiko library
Summary
Questions
Further reading
Building Graphical User Interfaces
Introduction to GUI
Using a library to create a GUI-based application
Installing and using the Apache Log Viewer app
Summary
Questions
Further reading
Working with Apache and Other Log Files
Parsing complex log files
The need for exceptions
Analyzing exceptions
Tricks for parsing different files
Error log
Access log
Common log format
Parsing other log files
Summary
Questions
Further reading
SOAP and REST API Communication
What is SOAP?
Using libraries for SOAP
What is a RESTful API?
Using standard libraries for RESTful APIs
Working with JSON data
Summary
Questions
Further reading
Web Scraping - Extracting Useful Data from Websites
What is web scraping?
Data extraction
The requests library
The beautifulsoup library
Extracting information from Wikipedia
Summary
Questions
Further reading
Statistics Gathering and Reporting
NumPY module
Using arrays and scalars
Array indexing
Indexing a 2D array
Universal array functions
Pandas module
Series
DataFrames
Data visualization
Matplotlib
Histograms
Scatter plots
Bar charts
Plotly
Scatter plots
Line scatter plots
Box plots
Contour plots
Summary
Questions
Further reading
MySQL and SQLite Database Administrations
MySQL database administration
Getting a database version
Creating a table and inserting data
Retrieving the data
Updating the data
Deleting the data
SQLite database administration
Connecting to the database
Creating a table
Inserting the data
Retrieving the data
Updating the data
Deleting the data
Summary
Questions
Further reading
Assessments
Chapter 1, Python Scripting Overview
Chapter 2, Debugging and Profiling Python Scripts
Chapter 3, Unit Testing – Introduction to the Unit Testing Framework
Chapter 4, Automating Regular Administrative Activities
Chapter 5, Handling Files, Directories, and Data
Chapter 6, File Archiving, Encrypting, and Decrypting
Chapter 7, Text Processing and Regular Expressions
Chapter 8, Documentation and Reporting
Chapter 9, Working with Various Files
Chapter 10, Basic Networking – Socket Programming
Chapter 11, Handling Emails Using Python Scripting
Chapter 12, Remote Monitoring of Hosts Over Telnet and SSH
Chapter 13, Building Graphical User Interfaces
Chapter 14, Working with Apache and Other Log Files
Chapter 15, SOAP and REST API Communication
Chapter 16, Web Scraping – Extracting Useful Data from Websites
Chapter 17, Statistics Gathering and Reporting
Chapter 18, MySQL and SQLite Database Administrations
Other Books You May Enjoy
Leave a review - let other readers know what you think
Preface
Python has evolved and extended its features toward every possible IT operation. This book will help you leverage the latest features of Python to write effective scripts and create command-line tools (for use when it comes to data types, loops, conditionals, functions, error handling, and more) to administer your environment. This book will revolve around the entire development process, from setup and planning to automated testing and building different command-line tools. This book gets you up and running with everything from basic scripting to using standard library packages. Finally, you will create a large scripting project where you will learn how to plan, implement, and distribute a project based on ideal resources.
Who this book is for
This book would be ideal for users with some basic understanding of Python programming who are interested in scaling their programming skills to command-line scripting and system administration.
Prior knowledge of Python is necessary.
What this book covers
Chapter 1, Python Scripting Overview, covers the installation procedures for Python as well as the use of the Python interpreter tool. You will learn how to assign values to variables and be introduced to variables and strings. You will study the sequence data types, including lists, tuples, sets, and dictionaries. Also, you will learn how to parse command-line options in scripts.
Chapter 2, Debugging and Profiling Python Scripts, teaches you how to debug Python programs using debugger tools. You will also learn how to handle errors, and explore the concepts of profiling and timing.
Chapter 3, Unit Testing – Introduction to the Unit Testing Framework, is about unit testing in Python. We will create unit tests to test programs.
Chapter 4, Automating Regular Administrative Activities, will teach you how to automate the regular administrative activities of the system administrator. You will learn about accepting inputs, handling passwords, the execution of external commands, reading config files, adding warning codes to scripts, implementing CPU limits, web browser launching, use of the os module, and taking backups.
Chapter 5, Handling Files, Directories, and Data, is where you will learn about using the os module for various activities. You will learn about the data and some methods applied to that data, such as copying, moving, merging, and comparing. You will also learn about the tarfile module and how to use it.
Chapter 6, File Archiving, Encrypting, and Decrypting, delves into file archiving, creating archives, and TAR and ZIP creation. You will also learn about unpacking the .tar and .zip files using applications.
Chapter 7, Text Processing and Regular Expressions, looks at text processing and regular expressions in Python. Python has a very powerful library of things called called regular expressions, which do tasks such as searching and extracting data. You will learn how to use regular expressions with files. You will also learn how to read and write to files.
Chapter 8, Documentation and Reporting, will teach you how to document and report information using Python. You will also learn how to take input using Python scripts and how to print the output. Using Python, you can write scripts for automated information gathering. Writing scripts for receiving emails is easier in Python. You will learn how to format information.
Chapter 9, Working with Various Files, will go into the issue of handling various files, such as PDF files, Excel files, and CSV files. You will learn how to open, edit, and get data from these files using Python.
Chapter 10, Basic Networking – Socket Programming, will first introduce the basics of networking; then you will learn about sockets such as TCP, UDP, and more. You will also learn about how to program sockets to communicate and get information of protocols such as HTTP and FTP.
Chapter 11, Handling Emails Using Python Scripting, explores how to compose and send emails using Python scripts. Sending emails is a very common task in any software program. We can use Python's smtplib module for sending emails in Python programs. In this chapter, you will also learn about the different protocols used for sending emails on different servers.
Chapter 12, Remote Monitoring of Hosts Over Telnet and SSH, shows you how to carry out basic configurations on a server with the SSH protocol. We will begin by using the Telnet module, after which we will implement the same configurations using the preferred method, SSH.
Chapter 13, Building Graphical User Interface, looks at graphical user interface creation with the PyQt module.
Chapter 14, Working with Apache and Other Log Files, explains how to work with Apache log files. You will also learn about log-parsing applications; that is, identifying the particular types of log messages. You will also learn how to parse these files and how to handle multiple files; detecting any exceptions, storing data, and producing reports.
Chapter 15, SOAP and REST API Communication, concerns the basics of SOAP and REST, and the differences between them. You will also get to know the SOAP API and how to use it using different libraries. We will also study the REST API and standard libraries.
Chapter 16, Web Scraping – Extracting Useful Data from Websites, will teach you about extracting data from a website using Python’s libraries. You will also learn how to search for articles and source code using Python.
Chapter 17, Statistics Gathering and Reporting, is about advanced Python libraries that are used in scientific calculations. These libraries are NumPy, SciPy, and Matplotlib. You will learn about the concepts of data visualization and learn how to plot data.
Chapter 18, MySQL and SQLite Database Administrations, looks at database administration using MySQL and SQLite databases. You will learn about the requirements and design for this kind of administration, how to modify the plugin framework, and how to write producer and consumer code.
To get the most out of this book
We wrote this book to be as accessible as possible and to teach you many different approaches to programming with Python through several scripts. However, to get the most out of them, you need to do the following:
Have a Linux system set up and configured for testing/debugging scripts
Understand the created scripts
Keep in mind what the components of each script are
Check how the components could be reused or combined in new ways
This book assumes a certain level of Python knowledge to begin your journey; these basic skills will not be covered in this book. These skills include the following:
How to set up and configure a Linux system
How to install, access, and configure a specific Python IDE (although several are already included in most Linux distributions)
Some basics about computing and programming (although we will do our best to provide a crash course)
Download the example code files
You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.
You can download the code files by following these steps:
Log in or register at
www.packt.com
.
Select the
SUPPORT
tab.
Click on
Code Downloads & Errata
.
Enter the name of the book in the
Search
box and follow the onscreen instructions.
Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:
WinRAR/7-Zip for Windows
Zipeg/iZip/UnRarX for Mac
7-Zip/PeaZip for Linux
The code bundle for the book is also hosted on GitHub https://github.com/PacktPublishing/Mastering-Python-Scripting-for-System-Administrators-/. In case there's an update to the code, it will be updated on the existing GitHub repository.
We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!
Conventions used
There are a number of text conventions used throughout this book.
CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: " To unpack the archives shutilmodule hasunpack_archive()function."
A block of code is set as follows:
>>> 3 * 'hi' + 'hello''hihihihello'
Any command-line input or output is written as follows:
sudo apt install python3-pip
Bold: Indicates a new term, an important word, or words that you see onscreen. Here is an example: " TheCSVformat, which stands forComma Separated Valuesformat."
Get in touch
Feedback from our readers is always welcome.
General feedback: If you have questions about any aspect of this book, mention the book title in the subject of your message and email us at [email protected].
Errata: Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you have found a mistake in this book, we would be grateful if you would report this to us. Please visit www.packt.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details.
Piracy: If you come across any illegal copies of our works in any form on the Internet, we would be grateful if you would provide us with the location address or website name. Please contact us at [email protected] with a link to the material.
If you are interested in becoming an author: If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, please visit authors.packtpub.com.
Reviews
Please leave a review. Once you have read and used this book, why not leave a review on the site that you purchased it from? Potential readers can then see and use your unbiased opinion to make purchase decisions, we at Packt can understand what you think about our products, and our authors can see your feedback on their book. Thank you!
For more information about Packt, please visit packt.com
Python Scripting Overview
Python is a scripting language, created by Guido van Rossum in 1991, which is used in various applications, such as game development, GIS programming, software development, web development, data analytics, machine learning, and system scripting.
Python is an object-oriented, high-level programming language with dynamic semantics. Mainly, Python is an interpreted language. Python is used for rapid application development, as it has all of the advanced features for development.
Python is simple and easy to learn, as its syntax makes programs more readable. Hence, the program maintenance cost is low.
Python has one more important feature of importing modules and packages. This feature allows for code reuse. The Python interpreter is easy to understand. We can write the complete code one by one in it and, as Python is an interpreted language, the code gets executed line by line. Python also has a wide range of libraries for advanced functionality.
This chapter will cover the following topics:
Python scripting
Installing and using Python and various tools
Variables, numbers, and strings
Python supported data structures and how to use all of these concepts in a script
Decision making; that is, the
if
statement
Looping statements; that is, the
for
and
while
loops
Functions
Modules
Technical requirements
Before you start reading this book, you should know the basics of Python programming, such as the basic syntax, variable types, tuple data type, list dictionary, functions, strings, and methods. Two versions, 3.7.2 and 2.7.15, are available at python.org/downloads/. In this book we'll work with version 3.7 for code examples and package installing.
Examples and source code for this chapter are available in the GitHub repository: https://github.com/PacktPublishing/Mastering-Python-Scripting-for-System-Administrators-.
Why Python?
Python has a wide range of libraries for open source data analysis tools, web frameworks, testing, and so on. Python is a programming language that can be used on different platforms (Windows, Mac, Linux, and embedded Linux H/W platforms, such as Raspberry Pi). It's used to develop desktop as well as web applications.
Developers can write programs with fewer lines if they use Python. Prototyping is very quick, as Python runs on an interpreter system. Python can be treated in an object-oriented, a procedural, or a functional way.
Python can do various tasks, such as creating web applications. It is used with the software to create workflows; it connects to database systems, handles files, handles big data, and performs complex mathematics.
Python syntax compared to other programming languages
The code written in Python is highly readable because it's similar to the English language. To complete a command, Python uses new lines.
Python has a great feature: indentation. Using indentations, we can define the scope for decision-making statements, loops such as for and while loops, functions, and classes.
Python installation
In this section, we will be learning about the installation of Python on different platforms, such as Linux and Windows.
Installation on the Linux platform
Most Linux distributions have Python 2 in their default installations. Some of them also have Python 3 included.
To install python3 on Debian-based Linux, run the following command in the Terminal:
sudo apt install python3
To install python3 on centos, run the following command in the Terminal:
sudo yum install python3
If you are unable to install Python using the preceding commands, download Python from https://www.python.org/downloads/ and follow the instructions.
Installation on the Windows platform
For installing Python in Microsoft Windows, you'll have to download the executable from python.org and install it. Download python.exe from https://www.python.org/downloads/ and choose the Python version that you want install on your PC. Then, double-click on the downloaded exe and install Python. On the installation wizard, there's checkbox that says Add Python to the path. Check this checkbox and then follow the instructions to install python3.
Installing and using pip to install packages
In Linux, install pip as follows:
sudo apt install python-pip --- This will install pip for python 2.
sudo apt install python3-pip --- This will install pip for python 3.
In Windows, install pip as follows:
python -m pip install pip
Installation on Mac
To install python3, first we must have brew installed on our system. To install brew on your system, run the following command:
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
By running the preceding command. brew will get installed. Now we will install python3 using brew:
brew install python3
Installing Jupyter notebook
For installing the Jupyter Notebook, download Anaconda.
Install the downloaded version of Anaconda and follow the instructions on the wizard.
Install Jupyter using pip:
pip install jupyter
In Linux, pip install jupyter will install Jupyter for python 2. If you want to install jupyter for python 3, run the following command:
pip3 install jupyter
Installing and using the virtual environment
Now we will see how to install the virtual environment and how to activate it.
To install the virtual environment on Linux, perform the following steps:
First check whether
pip
is installed or not. We are going to install
pip
for
python3
:
sudo apt install python3-pip
Install the virtual environment using
pip3
:
sudo pip3 install virtualenv
Now we will create the virtual environment. You can give it any name; I have called it
pythonenv
:
virtualenv pythonenv
Activate your virtual environment:
source venv/bin/activate
After your work is done, you can deactivate
virtualenv
by using following command:
deactivate
In Windows, run the pip install virtualenv command to install the virtual environment. The steps for installing virtualenv are same as with Linux.
Installing Geany and PyCharm
Download Geany from https://www.geany.org/download/releases and download the required binaries. Follow the instructions while installing.
Download PyCharm from https://www.jetbrains.com/pycharm/download/#section=windows and follow the instructions.
Python interpreter
Python is an interpreted language. It has an interactive console called the Python interpreter or Python shell. This shell provides a way to execute your program line by line without creating a script.
You can access all of Python's built-in functions and libraries, installed modules, and command history in the Python interactive console. This console gives you the opportunity to to explore Python. You're able to paste code into scripts when you are ready.
The difference between Python and Bash scripting
In this section, we're going to learn about the difference between Python and Bash scripting. The differences are as follows:
Python is a scripting language, whereas Bash is a shell used for entering and executing commands
Dealing with larger programs is easier with Python
In Python, you can do most things just by calling a one-line function from imported modules
Starting the interactive console
We can access Python's interactive console from any computer that has Python already installed. Run the following command to start Python's interactive console:
$ python
This will start the default Python interactive console.
In Linux, if we write Python in the Terminal, the python2.7 console starts. If you want to start the python3 console, then enter python3 in the Terminal and press Enter.
In Windows, when you enter Python in Command Prompt, it will start the console of the downloaded Python version.
Importing modules through the Python interpreter
If you are importing any module, then the Python interpreter checks if that module is available or not. You can do this by using the import statement. If that module is available, then you will see the >>> prefix after pressing the Enter key. This indicates that the execution was successful. If that module doesn't exist, the Python interpreter will show an error:
>>> import time
>>>
After importing the time module, we get the >>> prefix. This means that the module exists and this command gets executed successfully:
>>> import matplotlib
If the module doesn't exist, then you will get Traceback error:
File "<stdin>", line 1, in <module>
ImportError: No module named 'matplotlib'
So here, matplotlib isn't available, so it gives an error: ImportError: No module named 'matplotlib'.
To solve this error, we will have to install matplotlib and then again try to import matplotlib. After installing matplotlib, you should be able to import the module, as follows:
>>> import matplotlib
>>>
Exiting the Python console
We can come out of the Python console in two ways:
The keyboard shortcut:
Ctrl + D
Using the
quit()
or
exit()
functions
The keyboard shortcut
The keyboard shortcut, Ctrl + D, will give you the following code:
