Context-sensitive help enables you to quickly find which commands are available in each command mode, which
commands start with specific characters or group of characters, and which arguments and keywords are available to
particular commands. To access context-sensitive help, simply enter a question mark, ?, at the CLI.
Command syntax check verifies that a valid command was entered by the user. When a command is entered, the
command line interpreter evaluates the command from left to right. If the interpreter understands the command, the
requested action is executed, and the CLI returns to the appropriate prompt. However, if the interpreter cannot
understand the command being entered, it will provide feedback describing what is wrong with the command.