You have to source cvars to use these tools and run these commands in your git Linux kernel directory.

gg

gg does something like

git grep -n -E [other_options] "$(bli2 "$1")"

bli2

bli2() parses a string and transforms it into a more complex extended regexp, which it simply echoes.

To understand how it parses things try these:

bli2 "@V"
bli2 "@d"
bli2 " "
bli2 "
 "

Note that @V will catch the identifier of a simple local variable, @d will catch a number (even if it's a hex or 1ull), spaces are squeezed and parsed to match optional spaces.

bli2 pattern	description of what is echoed	echoed string (literally)	number of back-references
any space	optional space	`[[:space:]]*`	-
\!	exclamation mark (because bash otherwise bangs)	!	-
@S	obligatory space	`[[:space:]]+`	-
@V	identifier	`[[:alpha:]_]+[[:alnum:]_]*`	-
@K	identifier in only uppercases	`[[:upper:]_]+[[:upper:][:digit:]_]*`	-
@Q	a non-alnumeric	`[^[:alnum:]_]`	-
@Q2	a non-alnumeric or extension to the left of a variable	`[^[:alnum:]_>.]`	-
@w	(pointer) member, array	see `bli2 "@w"'	1
@d	any number	bli2 "@d"	1
@n	any number of lines, subsequent matches on the beginning of the next line	([^\n]\n)	1
\(...\)	up to 2 nested parentheses	bli2 "\(...\)"	2
\{...\}	up to 2 nested curly brackets	bli2 "\{...\}"	2
\[...\]	up to 2 nested square brackets	bli2 "\[...\]"	2
\(-..\)	characters optionally followed by up to 2 nested parentheses	bli2 "\(-..\)"	3
\{-..\}	characters optionally followed by up to 2 nested curly brackets	bli2 "\{-..\}"	3
\{.8.\}	up to 8 nested curly brackets	bli2 "\(.8.\)"	8
@...&\|@	prior conditions	bli2 "@...&\|@"	4
@&\|...@	later conditions	bli2 "@&\|...@"	4
@&\|...&\|@	conditions inbetween	bli2 "@&\|...&\|@"	4
@branch	a branch	bli2 "@branch"	3
@in_branch	in a branch	bli2 "@in_branch"	4

gres

I wrote this to do a multiline (git-)grep, See examples. gres does something in the order of:

git grep -E -n -other_opts "$(bli2 "$1")" -- '*.c' '*.h' | sed -n -r "$(ecsed2 "${@:2})"

with `gres -B1 -A40 "pattern1" "pattern2" "..."' the `-B1' and `-A40' are passed to git-grep, bli2() parses the first pattern to a extended regexp query. Subsequent patterns are passed to ecsed2() which are used to create a sed script. With this script, sed parses the `git grep' output and prints only the output of which the last - but not prior - patterns matched.

The sed script transforms the first of the `path/to/filename.c-301-' into a vi command, the remainder are removed. Until an end-of-function- or end-of-match-pattern occurs, lines are extended. Any comments are removed. For each match that `git grep' piped to sed, (parsed) matches are displayed if no exclusion pattern matched and the last pattern matched.