diff --git a/cwriter/util_bsd.go b/cwriter/util_bsd.go
new file mode 100644
index 0000000..4e3564e
--- /dev/null
+++ b/cwriter/util_bsd.go
@@ -0,0 +1,7 @@
+// +build darwin dragonfly freebsd netbsd openbsd
+
+package cwriter
+
+import "golang.org/x/sys/unix"
+
+const ioctlReadTermios = unix.TIOCGETA
diff --git a/cwriter/util_linux.go b/cwriter/util_linux.go
new file mode 100644
index 0000000..253f12d
--- /dev/null
+++ b/cwriter/util_linux.go
@@ -0,0 +1,7 @@
+// +build aix linux
+
+package cwriter
+
+import "golang.org/x/sys/unix"
+
+const ioctlReadTermios = unix.TCGETS
diff --git a/cwriter/util_solaris.go b/cwriter/util_solaris.go
new file mode 100644
index 0000000..4b29ff5
--- /dev/null
+++ b/cwriter/util_solaris.go
@@ -0,0 +1,7 @@
+// +build solaris
+
+package cwriter
+
+import "golang.org/x/sys/unix"
+
+const ioctlReadTermios = unix.TCGETA
diff --git a/cwriter/writer.go b/cwriter/writer.go
index 7d15717..6f57875 100644
--- a/cwriter/writer.go
+++ b/cwriter/writer.go
@@ -6,8 +6,6 @@
 	"io"
 	"os"
 	"strconv"
-
-	"github.com/mattn/go-isatty"
 )
 
 // NotATTY not a TeleTYpewriter error.
@@ -25,7 +23,7 @@
 	out        io.Writer
 	buf        bytes.Buffer
 	lineCount  int
-	fd         uintptr
+	fd         int
 	isTerminal bool
 }
 
@@ -33,8 +31,8 @@
 func New(out io.Writer) *Writer {
 	w := &Writer{out: out}
 	if f, ok := out.(*os.File); ok {
-		w.fd = f.Fd()
-		w.isTerminal = isatty.IsTerminal(w.fd)
+		w.fd = int(f.Fd())
+		w.isTerminal = IsTerminal(w.fd)
 	}
 	return w
 }
diff --git a/cwriter/writer_posix.go b/cwriter/writer_posix.go
index da4b215..f54a5d0 100644
--- a/cwriter/writer_posix.go
+++ b/cwriter/writer_posix.go
@@ -11,10 +11,16 @@
 }
 
 // GetSize returns the dimensions of the given terminal.
-func GetSize(fd uintptr) (width, height int, err error) {
-	ws, err := unix.IoctlGetWinsize(int(fd), unix.TIOCGWINSZ)
+func GetSize(fd int) (width, height int, err error) {
+	ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ)
 	if err != nil {
 		return -1, -1, err
 	}
 	return int(ws.Col), int(ws.Row), nil
 }
+
+// IsTerminal returns whether the given file descriptor is a terminal.
+func IsTerminal(fd int) bool {
+	_, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	return err == nil
+}
diff --git a/cwriter/writer_windows.go b/cwriter/writer_windows.go
index c04754b..1a69c81 100644
--- a/cwriter/writer_windows.go
+++ b/cwriter/writer_windows.go
@@ -5,7 +5,6 @@
 import (
 	"unsafe"
 
-	"github.com/mattn/go-isatty"
 	"golang.org/x/sys/windows"
 )
 
@@ -17,7 +16,8 @@
 )
 
 func (w *Writer) clearLines() error {
-	if !w.isTerminal && isatty.IsCygwinTerminal(w.fd) {
+	if !w.isTerminal {
+		// hope it's cygwin or similar
 		return w.ansiCuuAndEd()
 	}
 
@@ -31,7 +31,7 @@
 		info.CursorPosition.Y = 0
 	}
 	_, _, _ = procSetConsoleCursorPosition.Call(
-		w.fd,
+		uintptr(w.fd),
 		uintptr(uint32(uint16(info.CursorPosition.Y))<<16|uint32(uint16(info.CursorPosition.X))),
 	)
 
@@ -42,7 +42,7 @@
 	}
 	count := uint32(info.Size.X) * uint32(w.lineCount)
 	_, _, _ = procFillConsoleOutputCharacter.Call(
-		w.fd,
+		uintptr(w.fd),
 		uintptr(' '),
 		uintptr(count),
 		*(*uintptr)(unsafe.Pointer(cursor)),
@@ -54,7 +54,7 @@
 // GetSize returns the visible dimensions of the given terminal.
 //
 // These dimensions don't include any scrollback buffer height.
-func GetSize(fd uintptr) (width, height int, err error) {
+func GetSize(fd int) (width, height int, err error) {
 	var info windows.ConsoleScreenBufferInfo
 	if err := windows.GetConsoleScreenBufferInfo(windows.Handle(fd), &info); err != nil {
 		return 0, 0, err
@@ -64,3 +64,10 @@
 	// but looks like this is a root cause of issue #66, so removing both "+ 1" have fixed it.
 	return int(info.Window.Right - info.Window.Left), int(info.Window.Bottom - info.Window.Top), nil
 }
+
+// IsTerminal returns whether the given file descriptor is a terminal.
+func IsTerminal(fd int) bool {
+	var st uint32
+	err := windows.GetConsoleMode(windows.Handle(fd), &st)
+	return err == nil
+}