Run python programs in linux

How to Run a Python Program in Linux Using Shell Commands

Learn how to run a Python program in Linux using shell commands with this comprehensive guide. We cover the best practices for using os.system(), os.popen(), subprocess, making Python scripts executable, and running Python scripts in the terminal and bash scripts.

• Using os.system() and os.popen() to Execute Shell Commands with Python
• Making Python Scripts Executable in Linux
• Running Shell Commands using Python (Detailed Explanation)
• Using subprocess to Execute Shell Commands with Python
• Running Python Scripts in the Terminal
• Running a Python Script in a Bash Script
• Other helpful code examples for running a Python program in a Linux shell command are available in the accompanying source code
• Conclusion
• How do I run a Python program in Linux shell?
• How do I run a Python project in Python shell?
• Can you run Python in a bash shell?

If you’re new to Linux, running Python programs in the command line may seem like a daunting task. However, it is an essential skill to have as a programmer, and it can be a straightforward process with the right knowledge. In this article, we will explore the different ways to run a Python program within a Linux shell command.

Using os.system() and os.popen() to execute shell commands with python

One of the most straightforward ways to execute shell commands with Python is by using the os.system() method. This method executes a command in a subshell, and the output is sent to the standard output stream. The os.popen() method, on the other hand, is used to read output from a shell command. It returns a file-like object that can be used to read the output of the command.

Here is an example of how to use os.system() to execute a shell command:

This code will execute the ls -l command in a subshell and output the results to the console. It is important to note that the os.system() method is generally not recommended for security reasons.

If you need to capture the output of a shell command, you can use the os.popen() method. Here is an example:

import osoutput = os.popen('ls -l') print(output.read()) 

This code will execute the ls -l command in a subshell and capture the output to a variable called output . We can then print the output using the read() method of the output object.

When using os.system() and os.popen() , it is essential to follow best practices to ensure the security of your system. Here are a few best practices to keep in mind:

• Avoid using the os.system() method if possible.
• Always validate user input to prevent command injection attacks.
• Use the subprocess module instead of os.system() and os.popen() for more robust and secure execution of shell commands.

Making Python Scripts Executable in Linux

To run a Python script in Linux, you need to make it executable using the chmod command. Here’s how to do it:

This command makes the hello_world.py script executable. However, to run it, you also need to add a shebang line to the script. The shebang line tells the system what interpreter to use to run the script. Here’s an example of a shebang line for a Python script:

This shebang line tells the system to use the python interpreter to run the script. You can add this line to the beginning of your Python script to make it executable. Here’s an example of a Python script that prints “Hello, world!” to the console:

#!/usr/bin/env pythonprint("Hello, world!") 

To run this script, you need to navigate to the directory where the script is located and run it using the ./ notation:

Running Shell Commands using Python (Detailed Explanation)

In this video, learn how to run shell commands using Python. This is useful when your python Duration: 29:42

Using subprocess to Execute Shell Commands with Python

The subprocess module is a more robust and secure way of running shell commands in python. It provides more control over the execution of shell commands and supports more advanced features like input/output redirection, process management, and more.

Here is an example of how to use the subprocess.Popen() method to execute a shell command:

import subprocesssubprocess.Popen(['ls', '-l']) 

This code will execute the ls -l command and output the results to the console. The subprocess.Popen() method returns a Popen object that can be used to manage the process. This method is generally considered safer than using os.system() or os.popen() .

When using subprocess , here are some best practices to keep in mind:

• Always use the subprocess.call() or subprocess.run() method instead of the subprocess.Popen() method if possible.
• Always validate user input to prevent command injection attacks.
• Use the subprocess module instead of os.system() and os.popen() for more robust and secure execution of shell commands.

Running Python Scripts in the Terminal

Python programs can be started with the terminal or command line on all platforms. The py command can be used to run Python scripts under Windows. For Linux and macOS, you need to navigate to the directory where the Python script is located and run it with the python3 command. Here’s an example:

This command will execute the hello_world.py script and output “Hello, world!” to the console.

Running a Python Script in a Bash Script

You can run a Python script in a bash or shell script on macOS or Ubuntu. To do this, you need to add a shebang line to the beginning of the Python script, just like you would with a standalone Python script. Here’s an example of a bash script that runs a Python script:

#!/bin/bashpython3 hello_world.py 

This script will execute the hello_world.py script and output “Hello, world!” to the console.

Other helpful code examples for running a Python program in a Linux shell command are available in the accompanying source code

In python, python run shell command code example

import subprocess process = subprocess.Popen(['echo', 'More output'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) stdout, stderr = process.communicate() stdout, stderr 

In python, run linux command using python code example

import subprocess subprocess.call("command1") subprocess.call(["command1", "arg1", "arg2"])

In python, how to run linux command in python code example

import os cmd = 'your command here' os.system(cmd) 

In python, Shell script to run python code example

In the file job.sh, put this #!/bin/sh python python_script.py Execute this command to make the script runnable for you : chmod u+x job.sh Run it : ./job.sh

import subprocessprocess = subprocess.Popen(['echo', 'hi'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) out, err = process.communicate() print(out) # hi print(err) # None

In shell, python run shell command code example

# First, install python or python3. sudo apt-get install python #or sudo apt-get install python3# Then, run your python file. python /path-to-file/pyfile.py #or python3 /path-to-file/pyfile.py #Example python /home/person/randomfile.py #or python3 /home/person/randomfile.py# Hope this helped :)

Conclusion

In conclusion, there are several ways to run a Python program within a Linux shell command. Each method has its advantages and disadvantages, and it is crucial to understand them to choose the best approach for your project. By following the best practices outlined in this article, you can run your Python programs seamlessly within a Linux shell command.

Frequently Asked Questions — FAQs

What is the best way to run a Python program in a Linux shell command?

The best way to run a Python program in a Linux shell command depends on the specific requirements of your project. The methods covered in this post include using os.system(), os.popen(), subprocess.Popen(), making Python scripts executable, and running Python scripts in the terminal and bash scripts.

How do I make a Python script executable in Linux?

To make a Python script executable in Linux, you need to use the chmod +x command. Additionally, the first line of the Python script should start with #!/usr/bin/env python to be executable.

What is the difference between os.system() and os.popen()?

The os.system() method is used to execute shell commands with Python, whereas the os.popen() method is used to read output from a shell command.

How do I run a Python script in the terminal?

To run a Python script in the terminal, navigate to the directory where the script is located and run it with the python3 command.

Can I run a Python program in a bash script?

Yes, you can run a Python program in a bash script by including the command to run the Python script in the bash script. Additionally, the first line of the Python script should start with #!/usr/bin/env python to be executable.

What are the best practices for running Python scripts in a Linux shell command?

The best practices for running Python scripts in a Linux shell command include using the appropriate method for your project, making Python scripts executable, and following best practices for using os.system(), os.popen(), and subprocess. Additionally, it is important to ensure that your code is secure and follows proper coding standards.

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Run Python Scripts in Linux Command Line

This quick tip shows how to run Python programs from the Linux command line.

If you want to do something, it is pretty much guaranteed that there is a Python script for it. So, when you have a Python script, how do you run it?

The simplest way is to use the python or python3 command in the following manner:

Some distributions have used python2 as python and have an explicit command python3 for python3. So if you want Python 3 to be guaranteed, use python3 .

Method 1: Run it using python

The easiest method to run a Python script on any Linux distribution is by invoking the python command and provide it with the name of your Python script.

This will ensure that if the file’s contents are valid, it will be executed without any problems.

Method 2: Make Python script executable

You may have encountered executing bash scripts simply by typing out their relative/absolute path in the terminal. i.e. you never had to do a bash .sh like you do with Python scripts by typing python .py

In order to achieve this, a few things should be done first.

If you might have noticed, the bash scripts that you can execute by simply typing out their relative/absolute path, they are «executable» files.

To make your Python script executable, run the following command in your terminal:

This should be it. Right? I have a file hello.py , let’s try running it.

$ cat hello.py print("Hello Linux Handbook!") $ chmod +x hello.py $ ./hello.py ./hello.py: 1: Syntax error: word unexpected (expecting ")")

Uh oh. What? Syntax error? But it is a valid Python program/script.

The reason why we got this error is because by making hello.py an executable file, all we did was tell the shell that «You can execute it», but not what interpreter/program to use when it is being executed.

My shell (bash) thought that it was a bash script. And hence, we got this error.

The solution to overcome this is pretty simple. Add the following line to the first line of your Python script.

The #! syntax is used mostly in scripts (where you need an interpreter). Now, the /usr/bin/env part means that we are calling env to find the python command from $PATH and execute it for us.

This essentially starts Python for us, instead of the user needing to invoke it manually every time. And, if you don’t automate these things, are you even scripting?

Another reason to use env in shebang is to make it portable. Some systems have the Python executable interpreter stored as /usr/local/bin/python , while some might have /usr/bin/python .

Now, let’s try executing hello.py once again, but with the necessary changes made to it.

$ sed -i '1 i\#!/usr/bin/env python\n' hello.py $ cat hello.py #!/usr/bin/env python print("Hello Linux Handbook!") $ ./hello.py Hello Linux Handbook!

Oh hey! It runs flawlessly now.

Now that you know how to run Python programs from the terminal, how about learning to use Linux commands from Python scripts?

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