-1

I was recently using the subprocess module and it's run method to execute os commands through python only and get the output, since I was trying to make a custom command prompt in tkinter.

The way that command prompt handles commands I write into it is as follows -:

  1. So when I write a command as input I split it from spaces for e.g.

    INPUT: cmd exec python test.py

    OUTPUT: ['cmd', 'exec', 'python', 'test.py'] # i.e. [cmd, arg1, arg2, ...]

  2. Now I convert the above list into a dictionary with two keys -:

    • The first key is 'name' which has the value as the name of the command.
    • The second key is 'args' which is a concatenated string value (of all the other list items except the first list item from the first step).

    So it becomes -:

    command_input = {'name' : 'python', 'args' = 'test.py'} # i.e. {'name': cmd, 'args': concat_str_of_args}

  3. Now the dictionary made in the second process, is passed into a module, which interprets the command and it converts it into a normal command prompt command(NOTE: Previously the command was a custom one based on my own custom made syntax cmd exec command_prompt_command) in string form and returns it as a dict called command_output, with it's args as the list from step 1 ([cmd, arg1, arg2.....]).

    Like so -:

    command_output = my_module.convert_to_cmd_form(command_input) # returns a dictionary like so -: {'args' : ['python', 'test.py']}

Now I try executing a python script I made to test if this was working, The code for the test file is -:

# CODE FOR TEST FILE print('This is a special test for the terminal cmd integration!')

And executing this file by IDLE I get the desired output with no error:

This is a special test for the interstellar terminal cmd integration!

While when I do the same with my custom command prompt which in the backend uses a special subprocess python script to run this test.py it gives a name error:

Output of test.py using my script

And I am not able to properly understand the reason for the same the code for executing scripts is somewhat like so:

os.environ["PYTHONUNBUFFERED"] = "1" print([command_output['args'][0]], ' '.join(command_output['args'][1 : ]), ' '.join(command_output['args'][1 : ]).encode('utf-8')) result = subprocess.run([command_output['args'][0]], input = ' '.join(command_output['args'][1 : ]).encode('utf-8'), stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell = True, env = os.environ, cwd = 'C:')

The print statement here was for debugging to check if all values were being parsed as expected.

['python'] test.py b'test.py'
Improve this question
18
  • 1
    Please don't post images of code, data, or Tracebacks. Copy and paste it as text then format it as code (select it and type ctrl-k) ... Discourage screenshots of code and/or errors Commented Dec 5, 2020 at 15:36
  • 1
    Please include the complete test.py with your minimal reproducible example. Or enough or it that we can copy and paste into an editor and reproduce your results. Commented Dec 5, 2020 at 15:40
  • Actually I would have pasted the traceback but it is a gui I have made on which the output is showing where the text is displayed in a tkinter listbox and not selectable. Commented Dec 5, 2020 at 15:47
  • Also the complete code of test.py has been given theres only 1 line Commented Dec 5, 2020 at 15:48
  • Also thanks for the info about the proper way of posting tracebacks I'll surely keep in mind next time I post a question. Unfortunately in here the traceback cannot be copied exactly from the gui element and thus I have provided a screenshot. Commented Dec 5, 2020 at 15:56

1 Answer 1

Reset to default
1

my special subprocess python script to run this test.py it gives a name error:

Your mre from chat discussion:

import subprocess command_output = {'args':['python',r'test.py'] } result = subprocess.run([command_output['args'][0]], input = ' '.join(command_output['args'][1 : ]).encode('utf-8'), stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell = True, env = os.environ, cwd = 'C:')

Include the full path to the file to alleviate the NameError: name \'test\' is not defined\r\n' Exception.

command_output = {'args':['python',r'c:\full\path\test.py'] }

For the following solutions you would need to parse command_output appropriately.

This form works

args = ['python', '-m', 'test'] other = subprocess.run([args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell = True, env = os.environ, cwd = 'C:')

Using the input keyword argument, you need to send the python commands you would use if you were typing/executing from a python shell.

args = [b'python'] cmd = b'import test' another = subprocess.run(args, input = cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell = True, env = os.environ, cwd = 'C:')

This one courtesy of this answer https://stackoverflow.com/a/1027739/2823755. Again you may need to include the full path to the file.

args = [b'python'] cmd = b'''exec(open("test.py").read())''' another1 = subprocess.run(args, input = cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell = True, env = os.environ, cwd = 'C:')
Improve this answer
Sign up to request clarification or add additional context in comments.

5 Comments

The file itself resides in the C: directory only
Thx, I got it to work now I guess it was the cwd command that was not working and the current working directory was not changing thus it was picking up a local file and not the one in C: drive despite passing cwd arg as C: but as you mentioned writing full path makes it work! Thx
Now, if you think the question is understandable and can be useful to others in need please vote for reopening of the question.
@MatrixProgrammer: Sure ... but your question may need more detail - when I read your current edit I was still confused and had to review our chat discussion - which I based my answer on. Feel free to retract the acceptance if that is possible. If you came up with your own solution: Can I answer my own question?
Kindly review the question once more and tell me if its suitable now to be opened up again.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.