Where should I place my global 'gitattributes' file?

Question

I gather there is (despite the lack of documentation) a way to set Git attributes globally; but I'm not clear where to place the necessary gitattributes file. The instructions say they belong in

$(prefix)/etc/gitattributes 

But where is $(prefix)? In particular, where would it be for OS X (with Git in /usr/local/git/bin/git)? Alternately (or in addition) would ~/.gitattributes work?

Answer 1

Global vs. system-wide settings

There is some ambiguity in your question's terminology. In a Git context, "global" usually means "user-level"; in other words, a global setting affect all repositories for one specific user (the active one). In contrast, a system-wide setting affects all repositories for all users of a machine.

Repository-level gitattributes

(I'm only mentioning this for completeness.)

According to the relevant section of the Pro Git book,

If you wish to affect only a single repository (i.e., to assign attributes to files that are particular to one user’s workflow for that repository), then attributes should be placed in the $GIT_DIR/info/attributes file.

$GIT_DIR would typically expand to <path-to-repo-root-directory>/.git.

Global (user-level) gitattributes

According to the relevant section of the Pro Git book,

Attributes that should affect all repositories for a single user should be placed in a file specified by the core.attributesfile configuration option [...]. Its default value is $XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME is either not set or empty, $HOME/.config/git/attributes is used instead.

You can also run the following command,

git config --global core.attributesfile <path> 

to point Git to a custom path <path> for your global gitattributes file, e.g. ~/.gitattributes.

System-wide gitattributes

According to the relevant section of the Pro Git book,

Attributes for all users on a system should be placed in the $(prefix)/etc/gitattributes file.

which naturally begs the question:

[...] But where is $(prefix)?

See What is $(prefix) on $(prefix)/etc/gitconfig? for an answer. Unless you've assigned prefix a custom, non-empty value, $(prefix) expands to nothing by default; therefore, your system-wide gitattributes file should reside in /etc/.