text: """
  Display help information on the commands available within the shell.
  
  Additional help on each command can be found using the --help flag on the command in
  question.
  """
  import argparse
  import typing
  import re
  
  from reviser import commands
  from reviser import interactivity
  from reviser import templating
  
  HEADER_REGEX = re.compile(r"#+\s+")
  
  
  def get_completions(
      completer: "interactivity.ShellCompleter",
  ) -> typing.List[str]:
      """Get shell auto-completes for this command."""
      return []
  
  
  def populate_subparser(parser: argparse.ArgumentParser):
      """Populate parser for this command."""
      pass
  
  
  def _get_command_header_doc(name: str, docs: str) -> str:
      """Get the first paragraph of the command documentation."""
      lines = [
          line.rstrip()
          for line in (docs or "").split("\n")
          if not HEADER_REGEX.match(line)
      ]
      start_index = next((i for i, line in enumerate(lines) if line), 0)
  
      try:
          end_index = lines.index("", start_index) + 1
      except ValueError:
          end_index = len(lines) + 1
  
      aliases = ""
      if items := commands.REVERSED_ALIASES.get(name):
          aliases = "({}) ".format(", ".join(sorted(items)))
  
      return "{}{}".format(aliases, " ".join(lines[start_index:end_index]))
  
  
  def run(ex: "interactivity.Execution") -> "interactivity.Execution":
      """Display basic command help for the available shell commands."""
      command_docs = {
          name: _get_command_header_doc(name, docs)
          for name, command_module in commands.COMMANDS.items()
          if (docs := command_module.__doc__)
      }
      templating.printer(
          "commands/helper/help.jinja2",
          commands=list(sorted(command_docs.items(), key=lambda x: x[0])),
      )
      return ex.finalize(status="HELPED", message="Help displayed.")
  