--- a/doc/hg.1.txt
+++ b/doc/hg.1.txt
@@ -207,6 +207,31 @@ forget [options] [files]::
-I, --include <pat> include names matching the given patterns
-X, --exclude <pat> exclude names matching the given patterns
+grep [options] pattern [files]::
+ Search revisions of files for a regular expression.
+
+ This command behaves differently than Unix grep. It only accepts
+ Python/Perl regexps. It searches repository history, not the
+ working directory. It always prints the revision number in which
+ a match appears.
+
+ By default, grep only prints output for the first revision of a
+ file in which it finds a match. To get it to print every revision
+ that contains a change in match status ("-" for a match that
+ becomes a non-match, or "+" for a non-match that becomes a match),
+ use the --every-match flag.
+
+ options:
+ -0, --print0 end fields with NUL
+ -I, --include <pat> include names matching the given patterns
+ -X, --exclude <pat> exclude names matching the given patterns
+ -e, --every-match print every revision that matches
+ -i, --ignore-case ignore case when matching
+ -l, --files-with-matches print only file names and revs that match
+ -n, --line-number print matching line numbers
+ -r <rev>, --rev <rev> search in given revision range
+ -u, --user print user who committed change
+
heads::
Show all repository head changesets.