git/Documentation/config/grep.txt

grep.lineNumber::
	If set to true, enable `-n` option by default.

grep.column::
	If set to true, enable the `--column` option by default.

grep.patternType::
	Set the default matching behavior. Using a value of 'basic', 'extended',
	'fixed', or 'perl' will enable the `--basic-regexp`, `--extended-regexp`,
	`--fixed-strings`, or `--perl-regexp` option accordingly, while the
	value 'default' will use the `grep.extendedRegexp` option to choose
	between 'basic' and 'extended'.

grep.extendedRegexp::
	If set to true, enable `--extended-regexp` option by default. This
	option is ignored when the `grep.patternType` option is set to a value
	other than 'default'.

grep.threads::
	Number of grep worker threads to use. If unset (or set to 0), Git will
	use as many threads as the number of logical cores available.

grep.fullName::
	If set to true, enable `--full-name` option by default.

grep.fallbackToNoIndex::
	If set to true, fall back to `git grep --no-index` if `git grep`
	is executed outside of a git repository.  Defaults to false.