如何创建命令行文本编辑器？

import sys

def main():
    if len(sys.argv) < 2:
        print("Usage: python text_editor.py filename")
        return

    filename = sys.argv[1]

    with open(filename, "a+") as file:
        file.seek(0)
        content = file.read()
        print(content)

        while True:
            new_content = input(">> ")
            if new_content.lower() == "exit":
                break
            file.write(new_content + "\n")

if __name__ == "__main__":
    main()

python text_editor.py filename.txt