Shell Script: Execute a python program from within a shell script

You should be able to invoke it as python scriptname.py e.g.

# !/bin/bash

python /home/user/scriptname.py 

Also make sure the script has permissions to run.

You can make it executable by using chmod u+x scriptname.py.

Method 1 – Create a shell script:

Suppose you have a python file hello.py
Create a file called job.sh that contains

#!/bin/bash
python hello.py

mark it executable using

$ chmod +x job.sh

then run it

$ ./job.sh

Method 2 (BETTER) – Make the python itself run from shell:

Modify your script hello.py and add this as the first line

#!/usr/bin/env python

mark it executable using

$ chmod +x hello.py

then run it

$ ./hello.py

Imho, writing

python /path/to/script.py

Is quite wrong, especially in these days. Which python? python2.6? 2.7? 3.0? 3.1? Most of times you need to specify the python version in shebang tag of python file. I encourage to use

#!/usr/bin/env python2 #or python2.6 or python3 or even python3.1

for compatibility.

In such case, is much better to have the script executable and invoke it directly:

#!/bin/bash

/path/to/script.py

This way the version of python you need is only written in one file. Most of system these days are having python2 and python3 in the meantime, and it happens that the symlink python points to python3, while most people expect it pointing to python2.

This works best for me:
Add this at the top of the script:

#!c:/Python27/python.exe

(C:Python27python.exe is the path to the python.exe on my machine)
Then run the script via:

chmod +x script-name.py && script-name.py

This works for me:

1. Create a new shell file job. So let’s say:
   touch job.sh and add command to run python script (you can even add command line arguments to that python, I usually predefine my command line arguments).

   chmod +x job.sh

2. Inside job.sh add the following py files, let’s say:

   python_file.py argument1 argument2 argument3 >> testpy-output.txt && echo "Done with python_file.py"

   python_file1.py argument1 argument2 argument3 >> testpy-output.txt && echo "Done with python_file1.py"

Output of job.sh should look like this:

Done with python_file.py

Done with python_file1.py

I use this usually when I have to run multiple python files with different arguments, pre defined.

Note: Just a quick heads up on what’s going on here:

python_file.py argument1 argument2 argument3 >> testpy-output.txt && echo "completed with python_file.py" . 

• Here shell script will run the file python_file.py and add multiple command-line arguments at run time to the python file.
• This does not necessarily means, you have to pass command line arguments as well.
• You can just use it like: python python_file.py, plain and simple.
  Next up, the >> will print and store the output of this .py file in the testpy-output.txt file.
• && is a logical operator that will run only after the above is executed successfully and as an optional echo “completed with python_file.py” will be echoed on to your cli/terminal at run time.

I use this and it works fine

#/bin/bash
/usr/bin/python python python_script.py

Save the following program as print.py:

#!/usr/bin/python3
print('Hello World')

Then in the terminal type:

chmod +x print.py
./print.py

Since the other posts say everything (and I stumbled upon this post while looking for the following).
Here is a way how to execute a python script from another python script:

Python 2:

execfile("somefile.py", global_vars, local_vars)

Python 3:

with open("somefile.py") as f:
    code = compile(f.read(), "somefile.py", 'exec')
    exec(code, global_vars, local_vars)

and you can supply args by providing some other sys.argv

Here I have demonstrated an example to run python script within a shell script. For different purposes you may need to read the output from a shell command, execute both python script and shell command within the same file.

To execute a shell command from python use os.system() method. To read output from a shell command use os.popen().

Following is an example which will grep all processes having the text sample_program.py inside of it. Then after collecting the process IDs (using python) it will kill them all.

#!/usr/bin/python3
import os

# listing all matched processes and taking the output into a variable s
s = os.popen("ps aux | grep 'sample_program.py'").read()
s = 'n'.join([l for l in s.split('n') if "grep" not in l]) # avoiding killing the grep itself
print("To be killed:")
print(s)

# now manipulating this string s and finding the process IDs and killing them
os.system("kill -9 " + ' '.join([x.split()[1] for x in s.split('n') if x]))

References:

• Execute a python program from within a shell script
• Assign output of os.system to a variable and prevent it from being displayed on the screen

If you have a bash script and you need to run inside of it a python3 script (with external modules), I recommend that you point in your bash script to your python path like this.

#!/usr/bin/env bash

-- bash code --

/usr/bin/python3 your_python.py

-- bash code --

If there are some parameters need to transfer, how can I run the python source file in the shell.