You have to source [wiki:roelkluin/cvars 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 || see `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 || see `bli2 "\(...\)"' || 2 ||
|| \{...\} || up to 2 nested curly brackets || see `bli2 "\{...\}"' || 2 ||
|| \[...\] || up to 2 nested square brackets || see `bli2 "\[...\]"' || 2 ||
|| \(-..\) || characters optionally followed by up to 2 nested parentheses || see `bli2 "\(...\)"' || 3 ||
|| \{-..\} || characters optionally followed by up to 2 nested curly brackets || see `bli2 "\{...\}"' || 3 ||
|| \{.8.\} || up to 8 nested curly brackets || see `bli2 "\(...\)"' || 8 ||

= gres =
I wrote this to do a multiline (git-)grep

lets say we want to search for an erroneous pattern like this:
{{{
for (i = 0; i < n; i++) {}
...
if (i > n) ...
}}}
This is wrong because at the end of the loop i equals n and cannot be greater than n. We can match this with:
{{{
gres -B1 -A40 "@V < @d ;" \
"for \( (@V) = @d ;
         \1 < (@d) ;
         \1 \+\+ \)
    \{.8.\}
@n
if \( \1 > \3 \)"
}}}
For me - I currently have kernel version 2.6.33-rc2 - this results after a few seconds in:
{{{
--
---[ vi drivers/mmc/host/s3cmci.c +1209 ]---
	/* Set clock */
	for (mci_psc = 0; mci_psc < 255; mci_psc++) {
		host->real_rate = host->clk_rate / (host->clk_div*(mci_psc+1));

		if (host->real_rate <= ios->clock)
			break;
	}

	if (mci_psc > 255)
		mci_psc = 255;

	host->prescaler = mci_psc;
	writel(host->prescaler, host->base + S3C2410_SDIPRE);

	/* If requested clock is 0, real_rate will be 0, too */
	if (ios->clock == 0)
		host->real_rate = 0;
}}}
So how does it work? gres does something in the order of:
{{{
git grep -E -n -other_opts "$(bli2 "$1")" -- '*.c' '*.h' | sed -n -r "$(ecsed2 "${@:2})"
}}}
The {{{`}}}-B1' and {{{`}}}-A40' are passed to git-grep, bli2() parses the first pattern and subsequent patterns are passed to ecsed2().

= ecsed2 =
ecsed2() parses the `git grep' output and prints only the ones of which the last passed pattern matches, prior patterns (if any) are excluded.

More in detail, the first of the {{{`}}}path/to/filename.c-301-' is transformed 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.