Index: src/library/base/man/grep.Rd
===================================================================
--- src/library/base/man/grep.Rd	(revision 48319)
+++ src/library/base/man/grep.Rd	(working copy)
@@ -73,7 +73,7 @@
     \code{"\\9"} to parenthesized subexpressions of \code{pattern}.  For
     \code{perl = TRUE} only, it can also contain \code{"\\U"} or
     \code{"\\L"} to convert the rest of the replacement to upper or
-    lower case.
+    lower case, or \code{"\\E"} to end such case conversion.
   }
 }
 \details{


Index: src/main/pcre.c
===================================================================
--- src/main/pcre.c	(revision 48319)
+++ src/main/pcre.c	(working copy)
@@ -90,6 +90,9 @@
 	    } else if (p[1] == 'L') {
 		p++; n -= 2;
 		upper = FALSE; lower = TRUE;
+	    } else if (p[1] == 'E') { /* end case modification */
+		p++; n -= 2;
+		upper = FALSE; lower = FALSE;
 	    } else if (p[1] == 0) {
 		/* can't escape the final '\0' */
 		n--;
@@ -168,6 +171,9 @@
 	    } else if (p[1] == 'L') {
 		p += 2;
 		upper = FALSE; lower = TRUE;
+	    } else if (p[1] == 'E') { /* end case modification */
+		p += 2;
+		upper = FALSE; lower = FALSE;
 	    } else if (p[1] == 0) {
 		p += 1;
 	    } else {