Method command

lib/usage.ts:760–760

(
    cmd: string,
    description: string | undefined,
    isDefault: boolean,
    aliases: string[],
    deprecated?: boolean
  )

  clearCachedHelpMessage(): void;
  hasCachedHelpMessage(): boolean;
  command(
    cmd: string,
    description: string | undefined,
    isDefault: boolean,