CODEWITHSUNDEEP
python
Vikram
Vikram

Reputation: 149

How to get command prompt output which is in the form of .txt inside a python script?

I'm using this code os.system("dcapgen.exe C:\\Users\\folder\\a.dcap") in my python script to run this command dcapgen.exe C:\Users\folder\a.dcap. This command generates .txt file in its current directory. I want to use this generated .txt file further in my code. How to do this? I don't want command log output. Thanks! I'm new to python programming.

Upvotes: 0

Views: 81

Answers (4)

Vikram
Vikram

Reputation: 149

This cannot be done because .txt file that will be generated is not getting traced in command prompt. we can only get cmd log output using subprocess which is being suggested by other answers. so, we can get access to the generated file by using its path and full name which we know because its naming follows some pattern and location is fixed, like this

generated_text_file = original_file_name+"_some_addition.txt" with open(generated_text_file, 'r') as file1: s = file1.read().replace('/n','')

Upvotes: 0

heemayl
heemayl

Reputation: 42107

Use subprocess.run to run the command and capture STDOUT to get the output from the command:

proc = subprocess.run(['dcapgen.exe', 'C:\\Users\\folder\\a.dcap'], stdout=subprocess.PIPE, text=True)

Now you can get the STDOUT from the stdout attribute:

proc.stdout

You might need to strip-off CR-LF from end:

proc.stdout.rstrip()

Edit:

If you're using Python 2.7, you can use subprocess.check_output:

out = subprocess.check_output(['dcapgen.exe', 'C:\\Users\\folder\\a.dcap'])

Upvotes: 1

Giacomo Casoni
Giacomo Casoni

Reputation: 427

Let's assume you have a simple C program that writes "Hello World" to a text file, called text.txt, as follows:

#include <stdio.h>
#include <stdlib.h>

int main(){
  FILE * fp = fopen ("text.txt","w");
  fprintf(fp, "Hello world\n");
  fclose(fp);
  return 0;
}

Compiling the C program will give you an executable, in our case it will be called a.out. The command ./a.out will run the executable and print to file.

Now let's assume we have a Python script in the same folder. In order to execute the C program AND read from file you'll have to do something like this

import os

# Run the C generated executable
os.system('./a.out')

# At this point a `text.txt` file exists, so it can be accessed
# The "r" option means you want to read. "w" or "a" for write and append respectively
# The file is now accesible with assigned name `file` 
with open("text.txt", "r") as file:
  file.read() # To get the full content of the file
  file.readline() # To read a single line
  for line in file: # Handy way to traverse the file line by line
    print(line)

EDIT(s) If you want to follow through keep in mind that:

  1. This is a step-by-step Linux approach. I know little about Windows, but I am assuming executables are ran a bit differently. I'm sure you know how.
  2. If you have your files across different folders you'll need the path to the files to be specified, not just the file name.

Upvotes: 1

Tobias Feil
Tobias Feil

Reputation: 2696

Try the open method: here.

It is especially handy in Python that you can surround this method with a with clause.

Upvotes: 1

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