cmd — 基于行的命令行解析

处理命令

# cmd_simple.py
import cmd


class HelloWorld(cmd.Cmd):

    def do_greet(self, line):
        print("hello")

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    HelloWorld().cmdloop()

命令行参数

# cmd_arguments.py
import cmd


class HelloWorld(cmd.Cmd):

    def do_greet(self, person):
        """greet [person]
        Greet the named person"""
        if person:
            print("hi,", person)
        else:
            print('hi')

    def do_EOF(self, line):
        return True

    def postloop(self):
        print()


if __name__ == '__main__':
    HelloWorld().cmdloop()

Live Help

# cmd_do_help.py
# Set up gnureadline as readline if installed.
try:
    import gnureadline
    import sys
    sys.modules['readline'] = gnureadline
except ImportError:
    pass

import cmd


class HelloWorld(cmd.Cmd):

    def do_greet(self, person):
        if person:
            print("hi,", person)
        else:
            print('hi')

    def help_greet(self):
        print('\n'.join([
            'greet [person]',
            'Greet the named person',
        ]))

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    HelloWorld().cmdloop()

自动完成

# cmd_arg_completion.py
# Set up gnureadline as readline if installed.
try:
    import gnureadline
    import sys
    sys.modules['readline'] = gnureadline
except ImportError:
    pass

import cmd


class HelloWorld(cmd.Cmd):

    FRIENDS = ['Alice', 'Adam', 'Barbara', 'Bob']

    def do_greet(self, person):
        "Greet the person"
        if person and person in self.FRIENDS:
            greeting = 'hi, {}!'.format(person)
        elif person:
            greeting = 'hello, {}'.format(person)
        else:
            greeting = 'hello'
        print(greeting)

    def complete_greet(self, text, line, begidx, endidx):
        if not text:
            completions = self.FRIENDS[:]
        else:
            completions = [
                f
                for f in self.FRIENDS
                if f.startswith(text)
            ]
        return completions

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    HelloWorld().cmdloop()

重写基类方法

# cmd_illustrate_methods.py
# Set up gnureadline as readline if installed.
try:
    import gnureadline
    import sys
    sys.modules['readline'] = gnureadline
except ImportError:
    pass

import cmd


class Illustrate(cmd.Cmd):
    "Illustrate the base class method use."

    def cmdloop(self, intro=None):
        print('cmdloop({})'.format(intro))
        return cmd.Cmd.cmdloop(self, intro)

    def preloop(self):
        print('preloop()')

    def postloop(self):
        print('postloop()')

    def parseline(self, line):
        print('parseline({!r}) =>'.format(line), end='')
        ret = cmd.Cmd.parseline(self, line)
        print(ret)
        return ret

    def onecmd(self, s):
        print('onecmd({})'.format(s))
        return cmd.Cmd.onecmd(self, s)

    def emptyline(self):
        print('emptyline()')
        return cmd.Cmd.emptyline(self)

    def default(self, line):
        print('default({})'.format(line))
        return cmd.Cmd.default(self, line)

    def precmd(self, line):
        print('precmd({})'.format(line))
        return cmd.Cmd.precmd(self, line)

    def postcmd(self, stop, line):
        print('postcmd({}, {})'.format(stop, line))
        return cmd.Cmd.postcmd(self, stop, line)

    def do_greet(self, line):
        print('hello,', line)

    def do_EOF(self, line):
        "Exit"
        return True


if __name__ == '__main__':
    Illustrate().cmdloop('Illustrating the methods of cmd.Cmd')

通过属性配置Cmd

# cmd_attributes.py
import cmd


class HelloWorld(cmd.Cmd):

    prompt = 'prompt: '
    intro = "Simple command processor example."

    doc_header = 'doc_header'
    misc_header = 'misc_header'
    undoc_header = 'undoc_header'

    ruler = '-'

    def do_prompt(self, line):
        "Change the interactive prompt"
        self.prompt = line + ': '

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    HelloWorld().cmdloop()

运行Shell命令

# cmd_do_shell.py
import cmd
import subprocess


class ShellEnabled(cmd.Cmd):

    last_output = ''

    def do_shell(self, line):
        "Run a shell command"
        print("running shell command:", line)
        sub_cmd = subprocess.Popen(line,
                                   shell=True,
                                   stdout=subprocess.PIPE)
        output = sub_cmd.communicate()[0].decode('utf-8')
        print(output)
        self.last_output = output

    def do_echo(self, line):
        """Print the input, replacing '$out' with
        the output of the last shell command.
        """
        # Obviously not robust
        print(line.replace('$out', self.last_output))

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    ShellEnabled().cmdloop()

选择输入

# cmd_file.py
import cmd


class HelloWorld(cmd.Cmd):

    # Disable rawinput module use
    use_rawinput = False

    # Do not show a prompt after each command read
    prompt = ''

    def do_greet(self, line):
        print("hello,", line)

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    import sys
    with open(sys.argv[1], 'rt') as input:
        HelloWorld(stdin=input).cmdloop()

Commands from sys.argv

# cmd_argv.py
import cmd


class InteractiveOrCommandLine(cmd.Cmd):
    """Accepts commands via the normal interactive
    prompt or on the command line.
    """

    def do_greet(self, line):
        print('hello,', line)

    def do_EOF(self, line):
        return True


if __name__ == '__main__':
    import sys
    if len(sys.argv) > 1:
        InteractiveOrCommandLine().onecmd(' '.join(sys.argv[1:]))
    else:
        InteractiveOrCommandLine().cmdloop()