diff --git a/Makefile b/Makefile
index f184a8d4bb..2aa3586d02 100644
--- a/Makefile
+++ b/Makefile
@@ -215,7 +215,7 @@ LIB_OBJS = \
 
 BUILTIN_OBJS = \
 	builtin-log.o builtin-help.o builtin-count.o builtin-diff.o \
-	builtin-push.o
+	builtin-push.o builtin-grep.o
 
 GITLIBS = $(LIB_FILE) $(XDIFF_LIB)
 LIBS = $(GITLIBS) -lz
diff --git a/builtin-grep.c b/builtin-grep.c
new file mode 100644
index 0000000000..36150bf4ef
--- /dev/null
+++ b/builtin-grep.c
@@ -0,0 +1,454 @@
+/*
+ * Builtin "git grep"
+ *
+ * Copyright (c) 2006 Junio C Hamano
+ */
+#include "cache.h"
+#include "blob.h"
+#include "tree.h"
+#include "commit.h"
+#include "tag.h"
+#include "diff.h"
+#include "revision.h"
+#include "builtin.h"
+#include <regex.h>
+
+static int pathspec_matches(struct diff_options *opt, const char *name)
+{
+	int i, j;
+	int namelen;
+	if (!opt->nr_paths)
+		return 1;
+	namelen = strlen(name);
+	for (i = 0; i < opt->nr_paths; i++) {
+		const char *match = opt->paths[i];
+		int matchlen = opt->pathlens[i];
+		if (matchlen <= namelen) {
+			if (!strncmp(name, match, matchlen))
+				return 1;
+			continue;
+		}
+		/* If name is "Documentation" and pathspec is
+		 * "Documentation/", they should match.  Maybe
+		 * we would want to strip it in get_pathspec()???
+		 */
+		if (strncmp(name, match, namelen))
+			continue;
+		for (j = namelen; j < matchlen; j++)
+			if (match[j] != '/')
+				break;
+		if (matchlen <= j)
+			return 1;
+	}
+	return 0;
+}
+
+struct grep_opt {
+	const char *pattern;
+	regex_t regexp;
+	unsigned linenum:1;
+	unsigned invert:1;
+	int regflags;
+	unsigned pre_context;
+	unsigned post_context;
+};
+
+static char *end_of_line(char *cp, unsigned long *left)
+{
+	unsigned long l = *left;
+	while (l && *cp != '\n') {
+		l--;
+		cp++;
+	}
+	*left = l;
+	return cp;
+}
+
+static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
+		      const char *name, unsigned lno, char sign)
+{
+	printf("%s%c", name, sign);
+	if (opt->linenum)
+		printf("%d%c", lno, sign);
+	printf("%.*s\n", eol-bol, bol);
+}
+
+static int grep_buffer(struct grep_opt *opt, const char *name,
+		       char *buf, unsigned long size)
+{
+	char *bol = buf;
+	unsigned long left = size;
+	unsigned lno = 1;
+	struct pre_context_line {
+		char *bol;
+		char *eol;
+	} *prev = NULL, *pcl;
+	unsigned last_hit = 0;
+	unsigned last_shown = 0;
+	const char *hunk_mark = "";
+
+	if (opt->pre_context)
+		prev = xcalloc(opt->pre_context, sizeof(*prev));
+	if (opt->pre_context || opt->post_context)
+		hunk_mark = "--\n";
+
+	while (left) {
+		regmatch_t pmatch[10];
+		char *eol, ch;
+		int hit;
+
+		eol = end_of_line(bol, &left);
+		ch = *eol;
+		*eol = 0;
+
+		hit = !regexec(&opt->regexp, bol, ARRAY_SIZE(pmatch),
+			       pmatch, 0);
+		if (opt->invert)
+			hit = !hit;
+		if (hit) {
+			/* Hit at this line.  If we haven't shown the
+			 * pre-context lines, we would need to show them.
+			 */
+			if (opt->pre_context) {
+				unsigned from;
+				if (opt->pre_context < lno)
+					from = lno - opt->pre_context;
+				else
+					from = 1;
+				if (from <= last_shown)
+					from = last_shown + 1;
+				if (last_shown && from != last_shown + 1)
+					printf(hunk_mark);
+				while (from < lno) {
+					pcl = &prev[lno-from-1];
+					show_line(opt, pcl->bol, pcl->eol,
+						  name, from, '-');
+					from++;
+				}
+				last_shown = lno-1;
+			}
+			if (last_shown && lno != last_shown + 1)
+				printf(hunk_mark);
+			show_line(opt, bol, eol, name, lno, ':');
+			last_shown = last_hit = lno;
+		}
+		else if (last_hit &&
+			 lno <= last_hit + opt->post_context) {
+			/* If the last hit is within the post context,
+			 * we need to show this line.
+			 */
+			if (last_shown && lno != last_shown + 1)
+				printf(hunk_mark);
+			show_line(opt, bol, eol, name, lno, '-');
+			last_shown = lno;
+		}
+		if (opt->pre_context) {
+			memmove(prev+1, prev,
+				(opt->pre_context-1) * sizeof(*prev));
+			prev->bol = bol;
+			prev->eol = eol;
+		}
+		*eol = ch;
+		bol = eol + 1;
+		left--;
+		lno++;
+	}
+	return !!last_hit;
+}
+
+static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name)
+{
+	unsigned long size;
+	char *data;
+	char type[20];
+	int hit;
+	data = read_sha1_file(sha1, type, &size);
+	if (!data) {
+		error("'%s': unable to read %s", name, sha1_to_hex(sha1));
+		return 0;
+	}
+	hit = grep_buffer(opt, name, data, size);
+	free(data);
+	return hit;
+}
+
+static int grep_file(struct grep_opt *opt, const char *filename)
+{
+	struct stat st;
+	int i;
+	char *data;
+	if (lstat(filename, &st) < 0) {
+	err_ret:
+		if (errno != ENOENT)
+			error("'%s': %s", filename, strerror(errno));
+		return 0;
+	}
+	if (!st.st_size)
+		return 0; /* empty file -- no grep hit */
+	if (!S_ISREG(st.st_mode))
+		return 0;
+	i = open(filename, O_RDONLY);
+	if (i < 0)
+		goto err_ret;
+	data = xmalloc(st.st_size + 1);
+	if (st.st_size != xread(i, data, st.st_size)) {
+		error("'%s': short read %s", filename, strerror(errno));
+		close(i);
+		free(data);
+		return 0;
+	}
+	close(i);
+	i = grep_buffer(opt, filename, data, st.st_size);
+	free(data);
+	return i;
+}
+
+static int grep_cache(struct grep_opt *opt, struct rev_info *revs, int cached)
+{
+	int hit = 0;
+	int nr;
+	read_cache();
+
+	for (nr = 0; nr < active_nr; nr++) {
+		struct cache_entry *ce = active_cache[nr];
+		if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
+			continue;
+		if (!pathspec_matches(&revs->diffopt, ce->name))
+			continue;
+		if (cached)
+			hit |= grep_sha1(opt, ce->sha1, ce->name);
+		else
+			hit |= grep_file(opt, ce->name);
+	}
+	return hit;
+}
+
+static int grep_tree(struct grep_opt *opt, struct rev_info *revs,
+		     struct tree_desc *tree,
+		     const char *tree_name, const char *base)
+{
+	unsigned mode;
+	int len;
+	int hit = 0;
+	const char *path;
+	const unsigned char *sha1;
+	char *down_base;
+	char *path_buf = xmalloc(PATH_MAX + strlen(tree_name) + 100);
+
+	if (tree_name[0]) {
+		int offset = sprintf(path_buf, "%s:", tree_name);
+		down_base = path_buf + offset;
+		strcat(down_base, base);
+	}
+	else {
+		down_base = path_buf;
+		strcpy(down_base, base);
+	}
+	len = strlen(path_buf);
+
+	while (tree->size) {
+		int pathlen;
+		sha1 = tree_entry_extract(tree, &path, &mode);
+		pathlen = strlen(path);
+		strcpy(path_buf + len, path);
+
+		if (!pathspec_matches(&revs->diffopt, down_base))
+			;
+		else if (S_ISREG(mode))
+			hit |= grep_sha1(opt, sha1, path_buf);
+		else if (S_ISDIR(mode)) {
+			char type[20];
+			struct tree_desc sub;
+			void *data;
+			data = read_sha1_file(sha1, type, &sub.size);
+			if (!data)
+				die("unable to read tree (%s)",
+				    sha1_to_hex(sha1));
+			strcpy(path_buf + len + pathlen, "/");
+			sub.buf = data;
+			hit = grep_tree(opt, revs, &sub, tree_name, down_base);
+			free(data);
+		}
+		update_tree_entry(tree);
+	}
+	return hit;
+}
+
+static int grep_object(struct grep_opt *opt, struct rev_info *revs,
+		       struct object *obj, const char *name)
+{
+	if (!strcmp(obj->type, blob_type))
+		return grep_sha1(opt, obj->sha1, name);
+	if (!strcmp(obj->type, commit_type) ||
+	    !strcmp(obj->type, tree_type)) {
+		struct tree_desc tree;
+		void *data;
+		int hit;
+		data = read_object_with_reference(obj->sha1, tree_type,
+						  &tree.size, NULL);
+		if (!data)
+			die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
+		tree.buf = data;
+		hit = grep_tree(opt, revs, &tree, name, "");
+		free(data);
+		return hit;
+	}
+	die("unable to grep from object of type %s", obj->type);
+}
+
+static const char builtin_grep_usage[] =
+"git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
+
+int cmd_grep(int argc, const char **argv, char **envp)
+{
+	struct rev_info rev;
+	const char **dst, **src;
+	int err;
+	int hit = 0;
+	int no_more_arg = 0;
+	int seen_range = 0;
+	int seen_noncommit = 0;
+	int cached = 0;
+	struct grep_opt opt;
+	struct object_list *list;
+
+	memset(&opt, 0, sizeof(opt));
+	opt.regflags = REG_NEWLINE;
+
+	/*
+	 * Interpret and remove the grep options upfront.  Sigh...
+	 */
+	for (dst = src = &argv[1]; src < argc + argv; ) {
+		const char *arg = *src++;
+		if (!no_more_arg) {
+			if (!strcmp("--", arg)) {
+				no_more_arg = 1;
+				*dst++ = arg;
+				continue;
+			}
+			if (!strcmp("--cached", arg)) {
+				cached = 1;
+				continue;
+			}
+			if (!strcmp("-i", arg) ||
+			    !strcmp("--ignore-case", arg)) {
+				opt.regflags |= REG_ICASE;
+				continue;
+			}
+			if (!strcmp("-v", arg) ||
+			    !strcmp("--invert-match", arg)) {
+				opt.invert = 1;
+				continue;
+			}
+			if (!strcmp("-E", arg) ||
+			    !strcmp("--extended-regexp", arg)) {
+				opt.regflags |= REG_EXTENDED;
+				continue;
+			}
+			if (!strcmp("-G", arg) ||
+			    !strcmp("--basic-regexp", arg)) {
+				opt.regflags &= ~REG_EXTENDED;
+				continue;
+			}
+			if (!strcmp("-e", arg)) {
+				if (src < argc + argv) {
+					opt.pattern = *src++;
+					continue;
+				}
+				usage(builtin_grep_usage);
+			}
+			if (!strcmp("-n", arg)) {
+				opt.linenum = 1;
+				continue;
+			}
+			if (!strcmp("-H", arg)) {
+				/* We always show the pathname, so this
+				 * is a noop.
+				 */
+				continue;
+			}
+			if (!strcmp("-A", arg) ||
+			    !strcmp("-B", arg) ||
+			    !strcmp("-C", arg)) {
+				unsigned num;
+				if ((argc + argv <= src) ||
+				    sscanf(*src++, "%u", &num) != 1)
+					usage(builtin_grep_usage);
+				switch (arg[1]) {
+				case 'A':
+					opt.post_context = num;
+					break;
+				case 'C':
+					opt.post_context = num;
+				case 'B':
+					opt.pre_context = num;
+					break;
+				}
+				continue;
+			}
+		}
+		*dst++ = arg;
+	}
+	if (!opt.pattern)
+		die("no pattern given.");
+
+	err = regcomp(&opt.regexp, opt.pattern, opt.regflags);
+	if (err) {
+		char errbuf[1024];
+		regerror(err, &opt.regexp, errbuf, 1024);
+		regfree(&opt.regexp);
+		die("'%s': %s", opt.pattern, errbuf);
+	}
+
+	init_revisions(&rev);
+	*dst = NULL;
+	argc = setup_revisions(dst - argv, argv, &rev, NULL);
+
+	/*
+	 * Do not walk "grep -e foo master next pu -- Documentation/"
+	 * but do walk "grep -e foo master..next -- Documentation/".
+	 * Ranged request mixed with a blob or tree object, like
+	 * "grep -e foo v1.0.0:Documentation/ master..next"
+	 * so detect that and complain.
+	 */
+	for (list = rev.pending_objects; list; list = list->next) {
+		struct object *real_obj;
+		if (list->item->flags & UNINTERESTING)
+			seen_range = 1;
+		real_obj = deref_tag(list->item, NULL, 0);
+		if (strcmp(real_obj->type, commit_type))
+			seen_noncommit = 1;
+	}
+	if (!rev.pending_objects)
+		return !grep_cache(&opt, &rev, cached);
+	if (cached)
+		die("both --cached and revisions given.");
+
+	if (seen_range && seen_noncommit)
+		die("both A..B and non commit are given.");
+	if (seen_range) {
+		struct commit *commit;
+		prepare_revision_walk(&rev);
+		while ((commit = get_revision(&rev)) != NULL) {
+			unsigned char *sha1 = commit->object.sha1;
+			const char *n = find_unique_abbrev(sha1, rev.abbrev);
+			char rev_name[41];
+			strcpy(rev_name, n);
+			if (grep_object(&opt, &rev, &commit->object, rev_name))
+				hit = 1;
+			commit->buffer = NULL;
+		}
+		return !hit;
+	}
+
+	/* all of them are non-commit; do not walk, and
+	 * do not lose their names.
+	 */
+	for (list = rev.pending_objects; list; list = list->next) {
+		struct object *real_obj;
+		real_obj = deref_tag(list->item, NULL, 0);
+		if (grep_object(&opt, &rev, real_obj, list->name))
+			hit = 1;
+	}
+	return !hit;
+}
diff --git a/builtin.h b/builtin.h
index 8d5744fa42..7f06812b86 100644
--- a/builtin.h
+++ b/builtin.h
@@ -22,7 +22,7 @@ extern int cmd_log(int argc, const char **argv, char **envp);
 extern int cmd_format_patch(int argc, const char **argv, char **envp);
 extern int cmd_count_objects(int argc, const char **argv, char **envp);
 extern int cmd_diff(int argc, const char **argv, char **envp);
-
 extern int cmd_push(int argc, const char **argv, char **envp);
+extern int cmd_grep(int argc, const char **argv, char **envp);
 
 #endif
diff --git a/git.c b/git.c
index 6a771747eb..6d51add7d5 100644
--- a/git.c
+++ b/git.c
@@ -50,6 +50,7 @@ static void handle_internal_command(int argc, const char **argv, char **envp)
 		{ "count-objects", cmd_count_objects },
 		{ "diffn", cmd_diff },
 		{ "push", cmd_push },
+		{ "grep", cmd_grep },
 	};
 	int i;