How to view the available options for installing homebrew formula?

Question

I read this answer

Mac user and its receipt WARNING: Nokogiri was created against LibXML version 2.7.8, but dynamically loaded 2.7.3

and I just want to know where they found out about the --with-xml2-config option in

 brew install libxml2 --with-xml2-config 

so that I can check if I really want to use this parameter myself, and therefore I can better solve problems with the homebrew itself in the future.

How can I see a description of this particular parameter and, more generally, find out all the available formula parameters when using brew install?

I know that brew info FORMULA gets me such things, but brew info libxml2 only lists the options --universal , --without-python and --HEAD .

For more information, here is another question similar to this, but another: How can I get more information about the brew formula before installing?

Answer 1

First use options to check:

 brew options libxml2 

If this dose does not satisfy you, edit the rb file directly and do whatever you want:

 brew edit libxml2 

Answer 2

brew install ignores any parameters that it does not recognize. --with-xml2-config not a real libxml2 formula; he is simply ignored.

Answer 3

You can often see the available options in the .rb brew file. Open your favorite text editor, they usually live here on MacOS:

/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Formula/

you can also apply arguments to files, for example --enable-foo

these files usually do not contain a “description”, however