我们运行的是Linux，一个基本符合posix的操作系统。它应该是POSIX标准:实用程序参数语法。

An option is a hyphen followed by a single alphanumeric character, like this: -o. An option may require an argument (which must appear immediately after the option); for example, -o argument or -oargument. Options that do not require arguments can be grouped after a hyphen, so, for example, -lst is equivalent to -t -l -s. Options can appear in any order; thus -lst is equivalent to -tls. Options can appear multiple times. Options precede other nonoption arguments: -lst nonoption. The -- argument terminates options. The - option is typically used to represent one of the standard input streams.

看一下docopt。它是用于记录(和自动解析)命令行参数的正式标准。

例如……

Usage:
  my_program command --option <argument>
  my_program [<optional-argument>]
  my_program --another-option=<with-argument>
  my_program (--either-that-option | <or-this-argument>)
  my_program <repeating-argument> <repeating-argument>...

我认为命令行使用没有标准的语法，但大多数人都使用这样的约定:

微软命令行语法，IBM有类似的命令行语法

没有括号或大括号的文本 必须按所示输入的项 <尖括号内的文本> 必须为其提供值的占位符 [方括号内的文本] 可选项目 {括号内的文本} 一套必需的项目;选择一个 竖条{a|b} 互斥项的分隔符;选择一个 <file>… 可以重复的项目

GNU编码标准是一个很好的参考。本节处理——help的输出。在这种情况下，它不是很具体。打印一个表，显示短选项和长选项，并给出简洁的描述，可能不会出错。为了可读性，尽量让所有参数之间的间距合适。您可能希望为您的工具提供一个手册页(也可能是信息手册)，以提供更详细的解释。

我使用CSS形式符号表示。

Component values may be arranged into property values as follows: Several juxtaposed words mean that all of them must occur, in the given order. A bar (|) separates two or more alternatives: exactly one of them must occur. A double bar (||) separates two or more options: one or more of them must occur, in any order. A double ampersand (&&) separates two or more components, all of which must occur, in any order. Brackets ([ ]) are for grouping. Juxtaposition is stronger than the double ampersand, the double ampersand is stronger than the double bar, and the double bar is stronger than the bar. Thus, the following lines are equivalent: a b | c || d && e f [ a b ] | [ c || [ d && [ e f ]]] Every type, keyword, or bracketed group may be followed by one of the following modifiers: An asterisk (*) indicates that the preceding type, word, or group occurs zero or more times. A plus (+) indicates that the preceding type, word, or group occurs one or more times. A question mark (?) indicates that the preceding type, word, or group is optional. A pair of numbers in curly braces ({A,B}) indicates that the preceding type, word, or group occurs at least A and at most B times.

如果您需要示例，请参阅MDN上的正式定义部分;这里有一个字体:https://developer.mozilla.org/en-US/docs/Web/CSS/font#formal_syntax。

下面是我自己Pandoc小抄中的一个简单例子:

$ pandoc <input_file>.md --from [markdown|commonmark_x][-smart]? --to html --standalone --table-of-contents? --number-sections? [--css <style_sheet>.css]? --output <output_file>.html

通常，你的帮助输出应该包括:

Description of what the app does Usage syntax, which: Uses [options] to indicate where the options go arg_name for a required, singular arg [arg_name] for an optional, singular arg arg_name... for a required arg of which there can be many (this is rare) [arg_name...] for an arg for which any number can be supplied note that arg_name should be a descriptive, short name, in lower, snake case A nicely-formatted list of options, each: having a short description showing the default value, if there is one showing the possible values, if that applies Note that if an option can accept a short form (e.g. -l) or a long form (e.g. --list), include them together on the same line, as their descriptions will be the same Brief indicator of the location of config files or environment variables that might be the source of command line arguments, e.g. GREP_OPTS If there is a man page, indicate as such, otherwise, a brief indicator of where more detailed help can be found

进一步注意，同时接受-h和——help来触发这条消息是一种很好的形式，如果用户弄乱了命令行语法，例如遗漏了一个必需的参数，你应该显示这条消息。