捕获在终端中在变量中运行的命令的 output

Question

I am trying to capture all the data that I get from a python script that I run into a variable. I took a few inputs from the user within the script and I want to capture everything from start till the end.

It is almost similar to this: Running shell command and capturing the output

But again this uses the subprocess within the script to get an output.

What I want is something like this:

when i run ls -l in the terminal, I want my script to capture the ouput of ls -l

If i write:

p2 = subprocess.Popen('ls','-l',stdout= subprocess.PIPE).communicate()[0])

within my script, that will execute the script twice.

The expected output is to capture all the data when i run ls -l in the terminal to be captured in p2.

Answer 1

If you want to avoid all the hassle of using subprocess.Popen() explicitly, just go for os.popen("command").read() - it runs the former under the hood, and in my case the result of p2 = os.popen("ls -l").read() looks just right.

Answer 2

You can use pexpect to easily open a PTY and log everything it shows:

#!/usr/bin/env python3
import pexpect
import io

print("-- Running the program")
p = pexpect.spawn("./foo.py")
p.logfile_read = io.BytesIO()
p.interact();

print("-- Program exited. Here is the log:")
log = p.logfile_read.getvalue().decode("utf-8")
print(log)

Here's a foo.py :

#!/usr/bin/env python3
name=input("Enter name: ")
print("Hello " + name)

Here's what happens when you run it from a terminal:

$ ./foo.py
Enter name: World
Hello World

And here's what happens when you run it from the logging script:

$ ./log.py
-- Running the program
Enter name: World
Hello World
-- Program exited. Here is the log:
Enter name: World
Hello World