diff --git a/usr.bin/tail/extern.h b/usr.bin/tail/extern.h
index cdf6929d10bb..8c549a9f0bdc 100644
--- a/usr.bin/tail/extern.h
+++ b/usr.bin/tail/extern.h
@@ -52,8 +52,8 @@ struct mapinfo {
 
 enum STYLE { NOTSET = 0, FBYTES, FLINES, RBYTES, RLINES, REVERSE };
 
-void forward __P((FILE *, enum STYLE, long, struct stat *));
-void reverse __P((FILE *, enum STYLE, long, struct stat *));
+void forward __P((FILE *, enum STYLE, off_t, struct stat *));
+void reverse __P((FILE *, enum STYLE, off_t, struct stat *));
 
 int bytes __P((FILE *, off_t));
 int lines __P((FILE *, off_t));
diff --git a/usr.bin/tail/forward.c b/usr.bin/tail/forward.c
index cd1980f1e656..ceacc04213fd 100644
--- a/usr.bin/tail/forward.c
+++ b/usr.bin/tail/forward.c
@@ -58,7 +58,7 @@ static const char rcsid[] =
 #include <err.h>
 #include "extern.h"
 
-static void rlines __P((FILE *, long, struct stat *));
+static void rlines __P((FILE *, off_t, struct stat *));
 
 /* defines for inner loop actions */
 #define USE_SLEEP	0
@@ -91,7 +91,7 @@ void
 forward(fp, style, off, sbp)
 	FILE *fp;
 	enum STYLE style;
-	long off;
+	off_t off;
 	struct stat *sbp;
 {
 	int ch, kq = -1;
@@ -106,7 +106,7 @@ forward(fp, style, off, sbp)
 		if (S_ISREG(sbp->st_mode)) {
 			if (sbp->st_size < off)
 				off = sbp->st_size;
-			if (fseek(fp, off, SEEK_SET) == -1) {
+			if (fseeko(fp, off, SEEK_SET) == -1) {
 				ierr();
 				return;
 			}
@@ -137,7 +137,7 @@ forward(fp, style, off, sbp)
 	case RBYTES:
 		if (S_ISREG(sbp->st_mode)) {
 			if (sbp->st_size >= off &&
-			    fseek(fp, -off, SEEK_END) == -1) {
+			    fseeko(fp, -off, SEEK_END) == -1) {
 				ierr();
 				return;
 			}
@@ -154,7 +154,7 @@ forward(fp, style, off, sbp)
 	case RLINES:
 		if (S_ISREG(sbp->st_mode))
 			if (!off) {
-				if (fseek(fp, 0L, SEEK_END) == -1) {
+				if (fseeko(fp, (off_t)0, SEEK_END) == -1) {
 					ierr();
 					return;
 				}
@@ -226,7 +226,7 @@ forward(fp, style, off, sbp)
 				action = USE_SLEEP;
 			} else if (ev->data < 0) {
 				/* file shrank, reposition to end */
-				if (fseek(fp, 0L, SEEK_END) == -1) {
+				if (fseeko(fp, (off_t)0, SEEK_END) == -1) {
 					ierr();
 					return;
 				}
@@ -266,7 +266,7 @@ forward(fp, style, off, sbp)
 static void
 rlines(fp, off, sbp)
 	FILE *fp;
-	long off;
+	off_t off;
 	struct stat *sbp;
 {
 	struct mapinfo map;
diff --git a/usr.bin/tail/reverse.c b/usr.bin/tail/reverse.c
index 24468dd1a23a..83d21d9b00dd 100644
--- a/usr.bin/tail/reverse.c
+++ b/usr.bin/tail/reverse.c
@@ -56,7 +56,7 @@ static const char rcsid[] =
 #include "extern.h"
 
 static void r_buf __P((FILE *));
-static void r_reg __P((FILE *, enum STYLE, long, struct stat *));
+static void r_reg __P((FILE *, enum STYLE, off_t, struct stat *));
 
 /*
  * reverse -- display input in reverse order by line.
@@ -80,7 +80,7 @@ void
 reverse(fp, style, off, sbp)
 	FILE *fp;
 	enum STYLE style;
-	long off;
+	off_t off;
 	struct stat *sbp;
 {
 	if (style != REVERSE && off == 0)
@@ -111,7 +111,7 @@ static void
 r_reg(fp, style, off, sbp)
 	FILE *fp;
 	enum STYLE style;
-	long off;
+	off_t off;
 	struct stat *sbp;
 {
 	struct mapinfo map;
diff --git a/usr.bin/tail/tail.c b/usr.bin/tail/tail.c
index 911dcda00bf5..9b7d9a293ad7 100644
--- a/usr.bin/tail/tail.c
+++ b/usr.bin/tail/tail.c
@@ -71,7 +71,7 @@ main(argc, argv)
 {
 	struct stat sb;
 	FILE *fp;
-	long off;
+	off_t off;
 	enum STYLE style;
 	int ch, first;
 	char *p;
@@ -91,7 +91,7 @@ main(argc, argv)
 #define	ARG(units, forward, backward) {					\
 	if (style)							\
 		usage();						\
-	off = strtol(optarg, &p, 10) * (units);				\
+	off = strtoll(optarg, &p, 10) * (units);                        \
 	if (*p)								\
 		errx(1, "illegal offset -- %s", optarg);		\
 	switch(optarg[0]) {						\