Haskell 什么是mueval'；s——帮助参数？

阅读mueval文档时，我遇到了以下描述：

'有关每个选项的含义的信息，请参见--help的结果。'

什么是帮助？我如何使用它

在这里找到它：

---

这是我运行nix shell-p haskellPackages.mueval--运行'mueval--help'时得到的结果（我正在使用它运行mueval）：

---

mueval

在安装时作为命令行工具存在，因此文档引用了它（

mueval--help

）。

Usage: mueval [OPTION...] --expression EXPRESSION...
  -p PASSWORD    --password=PASSWORD      The password for the mubot account. If this is set, mueval will attempt to setuid to the mubot user. This is optional, as it requires the mubot user to be set up properly. (Currently a null-op.)
  -t TIME        --time-limit=TIME        Time limit for compilation and evaluation
  -l FILE        --load-file=FILE         A local file for Mueval to load, providing definitions. Contents are trusted! Do not put anything dubious in it!
  -m MODULE      --module=MODULE          A module we should import functions from for evaluation. (Can be given multiple times.)
  -n             --no-imports             Whether to import any default modules, such as Prelude; this is useful if you are loading a file which, say, redefines Prelude operators. This can be subverted by using --load-file.
  -E             --Extensions             Whether to enable the Glasgow extensions to Haskell '98. Defaults to false, but enabling is useful for QuickCheck.
  -X EXTENSION   --extension=EXTENSION    Pass additional flags enabling extensions just like you would to ghc. Example: -XViewPatterns
  -e EXPRESSION  --expression=EXPRESSION  The expression to be evaluated.
  -i             --inferred-type          Whether to enable printing of inferred type and the expression (as Mueval sees it). Defaults to false.
  -T             --type-only              Only print the expression and type, don't evaluate the expression. Defaults to false.
  -r             --resource-limits        Enable resource limits (using POSIX rlimits). Mueval does not by default since rlimits are broken on many systems.
  -S             --package-trust          Enable Safe-Haskell package trust system
  -s PACKAGE     --trust=PACKAGE          Specify a package to be trusted by Safe Haskell (ignored unless -S also present)
  -h             --help                   Prints out usage info.