Linux/Unix man page syntax conventions

Question

In man pages I come across various syntaxes to write Linux/Unix commands, which include square brackets, angular brackets, hyphens (-) and double h

Answer 1

There is also uncommon {} brackets used which from my search is for a required options that can be specified in mutually exclusive ways, ex {-A|--almost-all}.

 "{}" are used in conjunction with a vertical bar to
indicate cases where exactly one of the specified options may be used

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