无法在Python中执行top终端命令，求助定时保存内存信息方案

Hey there, let's work through this step by step to get your memory logging script up and running properly.

First, let's break down why your current approach isn't working:

• os.system() only returns the exit status code of the command (0 for success, non-zero for errors), not the actual output you see in the terminal. That's why your s=str(top) is just a number instead of the memory stats you need.
• You're opening the file in write mode ('w'), which overwrites the file every time—you want append mode ('a') to keep all historical records.
• The order of operations in your repeat() function is off; you should run the command and write to the file before setting the next timer to maintain consistent 10-second intervals.

Here's the corrected, working script #

import time
import threading
import subprocess

def log_memory_stats():
    # Get human-readable timestamp for each entry
    timestamp = time.ctime()
    
    try:
        # Execute the top command and capture its output directly
        # shell=True lets us use the pipe | operator in the command
        output = subprocess.check_output(
            "top -d 1.0 -n 1 | grep Mem",
            shell=True,
            text=True  # Returns string output instead of raw bytes
        )
        # Format the entry for readability
        log_entry = f"[{timestamp}]\n{output}\n"
        
        # Open file in append mode to preserve previous logs
        with open('ss.txt', 'a') as f:
            f.write(log_entry)
            
        print(f"Logged memory stats at {timestamp}")
        
    except subprocess.CalledProcessError as e:
        print(f"Error running command: {e}")
    
    # Schedule the next run exactly 10 seconds later
    threading.Timer(10, log_memory_stats).start()

# Start the monitoring loop
if __name__ == "__main__":
    print("Starting memory monitoring. Press Ctrl+C to stop.")
    log_memory_stats()
    # Keep the main thread alive so the timer can run
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        print("\nMonitoring stopped successfully.")

Key improvements explained: #

• subprocess.check_output(): This replaces os.system() and captures the actual text output of your command. The text=True parameter saves you from having to decode raw bytes into a string manually.
• Append mode ('a'): Using with open('ss.txt', 'a') ensures each new log entry is added to the end of the file, instead of wiping previous data.
• Error handling: The try-except block catches issues like command failures (e.g., top not being available, grep finding no matches) and prints a helpful message instead of crashing the script.
• Consistent scheduling: The timer is set after successfully logging the stats, so your 10-second interval stays reliable.
• Main thread keep-alive: The while True loop prevents the script from exiting immediately after setting the first timer.

Quick note about sudo: #

Most systems don't require sudo to run top, but if you do need it:

1. Run the entire Python script with sudo: sudo python3 your_script.py
2. Or configure passwordless sudo for the top command (edit /etc/sudoers carefully with visudo to avoid locking yourself out).

内容的提问来源于stack exchange，提问作者Shubham R