Python interactive shell with cmd module

basic_shell.py

import cmd

class BasicShell(cmd.Cmd):
    """Basic shell
    
    To create interactive shell, subclass the cmd.Cmd class.

    To start the shell, call the `cmdloop()` method, implemented in the base class.
    """

    def do_greet(self, argline):
        """Greet the user.
        
        Commands are implemented as methods. Method name is prefixed with "do_".
        The command method documentation (the docstring) is used by `Cmd` to provide help to the user.
        """
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell.
        
        To indicate that the session should finish, the command returns True.
        """
        print("Bye!")
        return True

if __name__ == "__main__":
    BasicShell().cmdloop()

basic_shell_eof.py

import cmd
import os

class BasicShell(cmd.Cmd):
    """Interactive shell example."""
    intro = "Welcome to BasicShell! For help type `?` or `help`.\n"
    prompt = "> "

    def do_greet(self, argline):
        """Greet the user."""
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell."""
        print("Bye!")
        return True

    def do_EOF(self, argline):
        """Exit the shell."""
        return self.do_bye(argline)
        
    def do_eval(self, argline):
        """Evaluate given expression and print the result."""
        try:
            print(eval(argline))
        except Exception as error:
            print(f"ERROR EVALUATING {argline}: {error}")

    def do_shell(self, argline):
        """Execute a shell command and print the output."""
        output = os.popen(argline).read()
        print(output)

    def emptyline(self):
        """Re-execute the last command"""
        print(f"REPEAT: {self.lastcmd}")
        super().emptyline()

if __name__ == "__main__":
    BasicShell().cmdloop()

basic_shell_eval.py

import cmd

class BasicShell(cmd.Cmd):
    """Interactive shell example."""
    prompt = "> "

    def do_greet(self, argline):
        """Greet the user."""
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell."""
        print("Bye!")
        return True

    def do_eval(self, argline):
        """Evaluate given expression and print the result."""
        try:
            print(eval(argline))
        except Exception as error:
            print(f"ERROR EVALUATING {argline}: {error}")

if __name__ == "__main__":
    BasicShell().cmdloop()

basic_shell_prompt.py

import cmd

class BasicShell(cmd.Cmd):
    prompt = "> "

    def do_greet(self, argline):
        """Greet the user.
        
        Commands are implemented as methods. Method name is prefixed with "do_".
        The command method documentation (the docstring) is used by `Cmd` to provide help to the user.
        """
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell.
        
        To indicate that the session should finish, the command returns True.
        """
        print("Bye!")
        return True

if __name__ == "__main__":
    BasicShell().cmdloop()

basic_shell_repeat.py

import cmd

class BasicShell(cmd.Cmd):
    """Interactive shell example."""
    intro = "Welcome to BasicShell! For help type `?` or `help`.\n"
    prompt = "> "

    def do_greet(self, argline):
        """Greet the user."""
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell."""
        print("Bye!")
        return True

    def do_eval(self, argline):
        """Evaluate given expression and print the result."""
        try:
            print(eval(argline))
        except Exception as error:
            print(f"ERROR EVALUATING {argline}: {error}")

    def emptyline(self):
        """Re-execute the last command"""
        print(f"REPEAT: {self.lastcmd}")
        super().emptyline()

if __name__ == "__main__":
    BasicShell().cmdloop()

basic_shell_shell.py

import cmd
import os

class BasicShell(cmd.Cmd):
    """Interactive shell example."""
    intro = "Welcome to BasicShell! For help type `?` or `help`.\n"
    prompt = "> "

    def do_greet(self, argline):
        """Greet the user."""
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell."""
        print("Bye!")
        return True

    def do_eval(self, argline):
        """Evaluate given expression and print the result."""
        try:
            print(eval(argline))
        except Exception as error:
            print(f"ERROR EVALUATING {argline}: {error}")

    def do_shell(self, argline):
        """Execute a shell command and print the output."""
        output = os.popen(argline).read()
        print(output)

    def emptyline(self):
        """Re-execute the last command"""
        print(f"REPEAT: {self.lastcmd}")
        super().emptyline()

if __name__ == "__main__":
    BasicShell().cmdloop()

basic_shell_welcome_message.py

import cmd

class BasicShell(cmd.Cmd):
    """Interactive shell example."""
    intro = "Welcome to BasicShell! For help type `?` or `help`.\n"
    prompt = "> "

    def do_greet(self, argline):
        """Greet the user."""
        if argline:
            print(f"Hello, {argline}!")
        else:
            print("Hello, stranger!")
    
    def do_bye(self, argline):
        """Exit the shell."""
        print("Bye!")
        return True

    def do_eval(self, argline):
        """Evaluate given expression and print the result."""
        try:
            print(eval(argline))
        except Exception as error:
            print(f"ERROR EVALUATING {argline}: {error}")

if __name__ == "__main__":
    BasicShell().cmdloop()