Top 10 Python Subprocess Programs 2023

Top 10 Python Subprocess Programs

You can use Python to write shell scripts by using the subprocess module to call shell commands, as well as the shlex module to parse shell commands.

Here's an example of how you might use Python to reverse the lines in a file using the tac command:

import subprocess import shlex # Open the file and read in the lines with open('file.txt', 'r') as f: lines = f.readlines() # Reverse the lines lines = reversed(lines) # Write the reversed lines back to the file with open('file.txt', 'w') as f: for line in lines: f.write(line) # Use the `tac` command to reverse the lines in the file command = 'tac file.txt' subprocess.call(shlex.split(command))

This script opens a file, reads in all of the lines, reverses them, and then writes them back to the file. It then uses the tac command to reverse the lines again.

You can use a similar approach to call other shell commands from within a Python script. Just make sure to use the subprocess module and the shlex module to properly parse and execute the commands.

python top 10 subprocess programing

1. Executing a simple shell command:

import subprocess

# Run the `ls` command

subprocess.run(['ls'])

2. Capturing the output of a shell command:

import subprocess # Run the `ls` command and capture the output output = subprocess.check_output(['ls']) print(output)

3. Executing a shell command and passing command-line arguments:

import subprocess # Run the `ls` command with the `-l` flag subprocess.run(['ls', '-l'])

4. Executing a shell command and capturing its exit code:

import subprocess # Run the `ls` command and capture the exit code result = subprocess.run(['ls']) print(result.returncode)

5. Executing a shell command and redirecting its output to a file:

import subprocess # Run the `ls` command and redirect its output to a file with open('output.txt', 'w') as f: subprocess.run(['ls'], stdout=f)

6. Executing a shell command and sending input to it via stdin:

import subprocess # Run the `wc` command and send input to it via stdin input_data = b'this is some input data\n' output = subprocess.run(['wc'], input=input_data, stdout=subprocess.PIPE) print(output.stdout)

7. Executing a shell command and suppressing its output:

import subprocess # Run the `ls` command and suppress its output subprocess.run(['ls'], stdout=subprocess.DEVNULL)

8. Executing a shell command in the background:

import subprocess # Run the `sleep` command in the background subprocess.Popen(['sleep', '10'])

9. Executing a shell command and waiting for it to complete:

import subprocess # Run the `sleep` command and wait for it to complete subprocess.run(['sleep', '10'])

1. Run a command and store its output in a variable:

import subprocess

output = subprocess.run(["ls", "-l"], capture_output=True).stdout
print(output)

2. Run a command and check its exit status:

import subprocess

try:
    subprocess.run(["false"], check=True)
except subprocess.CalledProcessError as err:
    print("Command failed with exit status", err.returncode)

3. Run a command with input supplied through stdin:

import subprocess

p = subprocess.run(["wc"], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
p.stdin.write(b"Hello, world!\n")
p.stdin.close()
print(p.stdout)

4. Run a command and redirect its output to a file:

import subprocess

with open("output.txt", "w") as f:
    subprocess.run(["ls", "-l"], stdout=f)

5. Run a command and specify the working directory:

import subprocess

subprocess.run(["git", "clone", "https://github.com/user/repo"], cwd="/path/to/directory")

6. Run a command and hide its output:

import subprocess

FNULL = open(os.devnull, "w")
subprocess.run(["command"], stdout=FNULL, stderr=FNULL)

7. Run a command and capture its output and error streams separately:

import subprocess

p = subprocess.run(["command"], stderr=subprocess.PIPE, stdout=subprocess.PIPE)
print(p.stdout)
print(p.stderr)

8. Run a command and pass environment variables to it:

import subprocess

env = os.environ.copy()
env["VARNAME"] = "varvalue"
subprocess.run(["command"], env=env)

9. Run a command and get its output as a string:

import subprocess

output = subprocess.run(["command"], capture_output=True, text=True).stdout
print(output)

10. Run a command and get its output as a list of lines:

import subprocess

output = subprocess.run(["command"], capture_output=True, text=True).stdout
lines = output.strip().split("\n")
print(lines)