Index: lib/libc/stdtime/strftime.3
===================================================================
--- lib/libc/stdtime/strftime.3
+++ lib/libc/stdtime/strftime.3
@@ -32,7 +32,7 @@
 .\"     @(#)strftime.3	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd June 25, 2012
+.Dd November 2, 2021
 .Dt STRFTIME 3
 .Os
 .Sh NAME
@@ -154,6 +154,8 @@
 is replaced by the minute as a decimal number (00-59).
 .It Cm %m
 is replaced by the month as a decimal number (01-12).
+.It Cm %N
+is replaced by the nanosecond as a decimal number (000000000-999999999).
 .It Cm %n
 is replaced by a newline.
 .It Cm %O*
@@ -257,6 +259,7 @@
 .Ql %h ,
 .Ql %k ,
 .Ql %l ,
+.Ql %N ,
 .Ql %n ,
 .Ql %O* ,
 .Ql \&%R ,
Index: lib/libc/stdtime/strftime.c
===================================================================
--- lib/libc/stdtime/strftime.c
+++ lib/libc/stdtime/strftime.c
@@ -41,6 +41,7 @@
 
 #include "tzfile.h"
 #include <fcntl.h>
+#include <time.h>
 #include <sys/stat.h>
 #include "un-namespace.h"
 #include "timelocal.h"
@@ -83,7 +84,9 @@
 #define	PAD_FMT_DAYOFYEAR	2
 	{ "%03d",	"%d",	"%3d",	"%03d" },
 #define	PAD_FMT_YEAR		3
-	{ "%04d",	"%d",	"%4d",	"%04d" }
+	{ "%04d",	"%d",	"%4d",	"%04d" },
+#define	PAD_FMT_NANOSECONDS	4
+	{ "%09d",	"%d",	"%9d",	"%09d" }
 };
 
 size_t
@@ -130,6 +133,7 @@
 _fmt(const char *format, const struct tm * const t, char *pt,
     const char * const ptlim, int *warnp, locale_t loc)
 {
+	struct timespec tspec;
 	int Ealternative, Oalternative, PadIndex;
 	struct lc_time_T *tptr = __get_current_time_locale(loc);
 
@@ -290,6 +294,12 @@
 					fmt_padding[PAD_FMT_MONTH][PadIndex],
 					pt, ptlim, loc);
 				continue;
+			case 'N':
+				clock_gettime(CLOCK_REALTIME_FAST, &tspec);
+				pt = _conv(tspec.tv_nsec,
+					fmt_padding[PAD_FMT_NANOSECONDS][PadIndex],
+					pt, ptlim, loc);
+				continue;
 			case 'n':
 				pt = _add("\n", pt, ptlim);
 				continue;