diff --git a/doc/Makefile b/doc/Makefile
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -28,7 +28,7 @@ hg.1.gendoc.txt: ../mercurial/commands.p
 
 install: man
 	for i in $(MAN) ; do \
-	  subdir=`echo $$i | sed -n 's/.\+\(\.[0-9]\)$$/man\1/p'` ; \
+	  subdir=`echo $$i | sed -n 's/.\+\.\([0-9]\)$$/man\1/p'` ; \
 	  mkdir -p $(MANDIR)/$$subdir ; \
 	  $(INSTALL) $$i $(MANDIR)/$$subdir ; \
 	done