diff --git a/Cargo.lock b/Cargo.lock
index 29f8e334cb..b3d5f48145 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -454,6 +454,7 @@ dependencies = [
  "nix",
  "notify",
  "os_pipe",
+ "pty",
  "rand 0.7.3",
  "regex",
  "remove_dir_all",
@@ -619,6 +620,17 @@ dependencies = [
  "syn 1.0.14",
 ]
 
+[[package]]
+name = "errno"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e2b2decb0484e15560df3210cf0d78654bb0864b2c138977c07e377a1bae0e2"
+dependencies = [
+ "kernel32-sys",
+ "libc",
+ "winapi 0.2.8",
+]
+
 [[package]]
 name = "failure"
 version = "0.1.6"
@@ -1508,6 +1520,16 @@ dependencies = [
  "unicode-xid 0.2.0",
 ]
 
+[[package]]
+name = "pty"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f50f3d255966981eb4e4c5df3e983e6f7d163221f547406d83b6a460ff5c5ee8"
+dependencies = [
+ "errno",
+ "libc",
+]
+
 [[package]]
 name = "qadapt-spin"
 version = "1.0.1"
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 52bc4f2c33..f09f8b6e45 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -72,3 +72,6 @@ nix = "0.14.1"
 
 [dev-dependencies]
 os_pipe = "0.9.1"
+
+[target.'cfg(unix)'.dev-dependencies]
+pty = "0.2"
diff --git a/cli/js/deno.ts b/cli/js/deno.ts
index e2052f7293..c563d5112c 100644
--- a/cli/js/deno.ts
+++ b/cli/js/deno.ts
@@ -90,7 +90,6 @@ export {
   dir,
   env,
   exit,
-  isTTY,
   execPath,
   hostname,
   loadavg,
@@ -124,6 +123,7 @@ export { statSync, lstatSync, stat, lstat } from "./stat.ts";
 export { symlinkSync, symlink } from "./symlink.ts";
 export { connectTLS, listenTLS } from "./tls.ts";
 export { truncateSync, truncate } from "./truncate.ts";
+export { isatty, setRaw } from "./tty.ts";
 export { utimeSync, utime } from "./utime.ts";
 export { version } from "./version.ts";
 export { writeFileSync, writeFile, WriteFileOptions } from "./write_file.ts";
diff --git a/cli/js/lib.deno.ns.d.ts b/cli/js/lib.deno.ns.d.ts
index b22d89ebeb..f94d284072 100644
--- a/cli/js/lib.deno.ns.d.ts
+++ b/cli/js/lib.deno.ns.d.ts
@@ -30,16 +30,6 @@ declare namespace Deno {
 
   export function runTests(opts?: RunTestsOptions): Promise<void>;
 
-  /** Check if running in terminal.
-   *
-   *       console.log(Deno.isTTY().stdout);
-   */
-  export function isTTY(): {
-    stdin: boolean;
-    stdout: boolean;
-    stderr: boolean;
-  };
-
   /** Get the loadavg. Requires the `--allow-env` flag.
    *
    *       console.log(Deno.loadavg());
@@ -492,6 +482,7 @@ declare namespace Deno {
     seekSync(offset: number, whence: SeekMode): void;
     close(): void;
   }
+
   /** An instance of `File` for stdin. */
   export const stdin: File;
   /** An instance of `File` for stdout. */
@@ -555,6 +546,20 @@ declare namespace Deno {
     /** Read-write. Behaves like `x` and allows to read from file. */
     | "x+";
 
+  // @url js/tty.d.ts
+
+  /** UNSTABLE: newly added API
+   *
+   *  Check if a given resource is TTY
+   */
+  export function isatty(rid: number): boolean;
+
+  /** UNSTABLE: newly added API
+   *
+   *  Set TTY to be under raw mode or not.
+   */
+  export function setRaw(rid: number, mode: boolean): void;
+
   // @url js/buffer.d.ts
 
   /** A Buffer is a variable-sized buffer of bytes with read() and write()
diff --git a/cli/js/os.ts b/cli/js/os.ts
index 2a68ff8d33..309f5e1ff2 100644
--- a/cli/js/os.ts
+++ b/cli/js/os.ts
@@ -3,13 +3,6 @@ import { sendSync } from "./dispatch_json.ts";
 import { errors } from "./errors.ts";
 import * as util from "./util.ts";
 
-/** Check if running in terminal.
- *
- *       console.log(Deno.isTTY().stdout);
- */
-export function isTTY(): { stdin: boolean; stdout: boolean; stderr: boolean } {
-  return sendSync("op_is_tty");
-}
 /** Get the loadavg.
  * Requires the `--allow-env` flag.
  *
diff --git a/cli/js/os_test.ts b/cli/js/os_test.ts
index 6e771fe989..cdf72fdd7e 100644
--- a/cli/js/os_test.ts
+++ b/cli/js/os_test.ts
@@ -115,10 +115,6 @@ test(function osPid(): void {
   assert(Deno.pid > 0);
 });
 
-test(function osIsTTYSmoke(): void {
-  console.log(Deno.isTTY());
-});
-
 testPerm({ env: true }, function getDir(): void {
   type supportOS = "mac" | "win" | "linux";
 
diff --git a/cli/js/tty.ts b/cli/js/tty.ts
new file mode 100644
index 0000000000..2ad44d025e
--- /dev/null
+++ b/cli/js/tty.ts
@@ -0,0 +1,14 @@
+import { sendSync } from "./dispatch_json.ts";
+
+/** Check if a given resource is TTY. */
+export function isatty(rid: number): boolean {
+  return sendSync("op_isatty", { rid });
+}
+
+/** Set TTY to be under raw mode or not. */
+export function setRaw(rid: number, mode: boolean): void {
+  sendSync("op_set_raw", {
+    rid,
+    mode
+  });
+}
diff --git a/cli/js/tty_test.ts b/cli/js/tty_test.ts
new file mode 100644
index 0000000000..f58784a7cd
--- /dev/null
+++ b/cli/js/tty_test.ts
@@ -0,0 +1,22 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { test, testPerm, assert } from "./test_util.ts";
+
+// Note tests for Deno.setRaw is in integration tests.
+
+testPerm({ read: true }, function isatty(): void {
+  // CI not under TTY, so cannot test stdin/stdout/stderr.
+  const f = Deno.openSync("cli/tests/hello.txt");
+  assert(!Deno.isatty(f.rid));
+});
+
+test(function isattyError(): void {
+  let caught = false;
+  try {
+    // Absurdly large rid.
+    Deno.isatty(0x7fffffff);
+  } catch (e) {
+    caught = true;
+    assert(e instanceof Deno.errors.BadResource);
+  }
+  assert(caught);
+});
diff --git a/cli/js/unit_tests.ts b/cli/js/unit_tests.ts
index 1c82374663..2495c938bf 100644
--- a/cli/js/unit_tests.ts
+++ b/cli/js/unit_tests.ts
@@ -54,6 +54,7 @@ import "./text_encoding_test.ts";
 import "./timers_test.ts";
 import "./tls_test.ts";
 import "./truncate_test.ts";
+import "./tty_test.ts";
 import "./url_test.ts";
 import "./url_search_params_test.ts";
 import "./utime_test.ts";
diff --git a/cli/ops/files.rs b/cli/ops/files.rs
index 4bf8b16887..916cbdc69a 100644
--- a/cli/ops/files.rs
+++ b/cli/ops/files.rs
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 use super::dispatch_json::{Deserialize, JsonOp, Value};
-use super::io::StreamResource;
+use super::io::{FileMetadata, StreamResource};
 use crate::fs as deno_fs;
 use crate::op_error::OpError;
 use crate::state::State;
@@ -125,9 +125,10 @@ fn op_open(
   let fut = async move {
     let fs_file = open_options.open(filename).await?;
     let mut state = state_.borrow_mut();
-    let rid = state
-      .resource_table
-      .add("fsFile", Box::new(StreamResource::FsFile(fs_file)));
+    let rid = state.resource_table.add(
+      "fsFile",
+      Box::new(StreamResource::FsFile(fs_file, FileMetadata::default())),
+    );
     Ok(json!(rid))
   };
 
@@ -197,7 +198,7 @@ fn op_seek(
     .ok_or_else(OpError::bad_resource)?;
 
   let tokio_file = match resource {
-    StreamResource::FsFile(ref file) => file,
+    StreamResource::FsFile(ref file, _) => file,
     _ => return Err(OpError::bad_resource()),
   };
   let mut file = futures::executor::block_on(tokio_file.try_clone())?;
diff --git a/cli/ops/io.rs b/cli/ops/io.rs
index 8edb1f748e..ad3949a032 100644
--- a/cli/ops/io.rs
+++ b/cli/ops/io.rs
@@ -57,7 +57,7 @@ pub fn init(i: &mut Isolate, s: &State) {
 }
 
 pub fn get_stdio() -> (StreamResource, StreamResource, StreamResource) {
-  let stdin = StreamResource::Stdin(tokio::io::stdin());
+  let stdin = StreamResource::Stdin(tokio::io::stdin(), TTYMetadata::default());
   let stdout = StreamResource::Stdout({
     let stdout = STDOUT_HANDLE
       .try_clone()
@@ -69,11 +69,25 @@ pub fn get_stdio() -> (StreamResource, StreamResource, StreamResource) {
   (stdin, stdout, stderr)
 }
 
+#[cfg(unix)]
+use nix::sys::termios;
+
+#[derive(Default)]
+pub struct TTYMetadata {
+  #[cfg(unix)]
+  pub mode: Option<termios::Termios>,
+}
+
+#[derive(Default)]
+pub struct FileMetadata {
+  pub tty: TTYMetadata,
+}
+
 pub enum StreamResource {
-  Stdin(tokio::io::Stdin),
+  Stdin(tokio::io::Stdin, TTYMetadata),
   Stdout(tokio::fs::File),
   Stderr(tokio::io::Stderr),
-  FsFile(tokio::fs::File),
+  FsFile(tokio::fs::File, FileMetadata),
   TcpStream(tokio::net::TcpStream),
   ServerTlsStream(Box<ServerTlsStream<TcpStream>>),
   ClientTlsStream(Box<ClientTlsStream<TcpStream>>),
@@ -101,8 +115,8 @@ impl DenoAsyncRead for StreamResource {
   ) -> Poll<Result<usize, OpError>> {
     use StreamResource::*;
     let mut f: Pin<Box<dyn AsyncRead>> = match self {
-      FsFile(f) => Box::pin(f),
-      Stdin(f) => Box::pin(f),
+      FsFile(f, _) => Box::pin(f),
+      Stdin(f, _) => Box::pin(f),
       TcpStream(f) => Box::pin(f),
       ClientTlsStream(f) => Box::pin(f),
       ServerTlsStream(f) => Box::pin(f),
@@ -203,7 +217,7 @@ impl DenoAsyncWrite for StreamResource {
   ) -> Poll<Result<usize, OpError>> {
     use StreamResource::*;
     let mut f: Pin<Box<dyn AsyncWrite>> = match self {
-      FsFile(f) => Box::pin(f),
+      FsFile(f, _) => Box::pin(f),
       Stdout(f) => Box::pin(f),
       Stderr(f) => Box::pin(f),
       TcpStream(f) => Box::pin(f),
@@ -220,7 +234,7 @@ impl DenoAsyncWrite for StreamResource {
   fn poll_flush(&mut self, cx: &mut Context) -> Poll<Result<(), OpError>> {
     use StreamResource::*;
     let mut f: Pin<Box<dyn AsyncWrite>> = match self {
-      FsFile(f) => Box::pin(f),
+      FsFile(f, _) => Box::pin(f),
       Stdout(f) => Box::pin(f),
       Stderr(f) => Box::pin(f),
       TcpStream(f) => Box::pin(f),
diff --git a/cli/ops/mod.rs b/cli/ops/mod.rs
index 7746143dbe..32d4e3b965 100644
--- a/cli/ops/mod.rs
+++ b/cli/ops/mod.rs
@@ -28,5 +28,6 @@ pub mod runtime_compiler;
 pub mod signal;
 pub mod timers;
 pub mod tls;
+pub mod tty;
 pub mod web_worker;
 pub mod worker_host;
diff --git a/cli/ops/os.rs b/cli/ops/os.rs
index c0479c656c..2df9470ddb 100644
--- a/cli/ops/os.rs
+++ b/cli/ops/os.rs
@@ -2,7 +2,6 @@
 use super::dispatch_json::{Deserialize, JsonOp, Value};
 use crate::op_error::OpError;
 use crate::state::State;
-use atty;
 use deno_core::*;
 use std::collections::HashMap;
 use std::env;
@@ -12,7 +11,6 @@ use url::Url;
 
 pub fn init(i: &mut Isolate, s: &State) {
   i.register_op("op_exit", s.stateful_json_op(op_exit));
-  i.register_op("op_is_tty", s.stateful_json_op(op_is_tty));
   i.register_op("op_env", s.stateful_json_op(op_env));
   i.register_op("op_exec_path", s.stateful_json_op(op_exec_path));
   i.register_op("op_set_env", s.stateful_json_op(op_set_env));
@@ -151,18 +149,6 @@ fn op_exit(
   std::process::exit(args.code)
 }
 
-fn op_is_tty(
-  _s: &State,
-  _args: Value,
-  _zero_copy: Option<ZeroCopyBuf>,
-) -> Result<JsonOp, OpError> {
-  Ok(JsonOp::Sync(json!({
-    "stdin": atty::is(atty::Stream::Stdin),
-    "stdout": atty::is(atty::Stream::Stdout),
-    "stderr": atty::is(atty::Stream::Stderr),
-  })))
-}
-
 fn op_loadavg(
   state: &State,
   _args: Value,
diff --git a/cli/ops/process.rs b/cli/ops/process.rs
index 9da87bd396..82ac25bbee 100644
--- a/cli/ops/process.rs
+++ b/cli/ops/process.rs
@@ -33,7 +33,7 @@ fn clone_file(rid: u32, state: &State) -> Result<std::fs::File, OpError> {
     .get_mut::<StreamResource>(rid)
     .ok_or_else(OpError::bad_resource)?;
   let file = match repr {
-    StreamResource::FsFile(ref mut file) => file,
+    StreamResource::FsFile(ref mut file, _) => file,
     _ => return Err(OpError::bad_resource()),
   };
   let tokio_file = futures::executor::block_on(file.try_clone())?;
diff --git a/cli/ops/tty.rs b/cli/ops/tty.rs
new file mode 100644
index 0000000000..e83d2edfdc
--- /dev/null
+++ b/cli/ops/tty.rs
@@ -0,0 +1,246 @@
+use super::dispatch_json::JsonOp;
+use super::io::StreamResource;
+use crate::op_error::OpError;
+use crate::ops::json_op;
+use crate::state::State;
+use atty;
+use deno_core::*;
+#[cfg(unix)]
+use nix::sys::termios;
+use serde_derive::Deserialize;
+use serde_json::Value;
+
+#[cfg(windows)]
+use winapi::shared::minwindef::DWORD;
+#[cfg(windows)]
+use winapi::um::wincon;
+#[cfg(windows)]
+const RAW_MODE_MASK: DWORD = wincon::ENABLE_LINE_INPUT
+  | wincon::ENABLE_ECHO_INPUT
+  | wincon::ENABLE_PROCESSED_INPUT;
+#[cfg(windows)]
+fn get_windows_handle(
+  f: &std::fs::File,
+) -> Result<std::os::windows::io::RawHandle, OpError> {
+  use std::os::windows::io::AsRawHandle;
+  use winapi::um::handleapi;
+
+  let handle = f.as_raw_handle();
+  if handle == handleapi::INVALID_HANDLE_VALUE {
+    return Err(OpError::from(std::io::Error::last_os_error()));
+  } else if handle.is_null() {
+    return Err(OpError::other("null handle".to_owned()));
+  }
+  Ok(handle)
+}
+
+pub fn init(i: &mut Isolate, s: &State) {
+  i.register_op("op_set_raw", s.core_op(json_op(s.stateful_op(op_set_raw))));
+  i.register_op("op_isatty", s.core_op(json_op(s.stateful_op(op_isatty))));
+}
+
+#[cfg(windows)]
+macro_rules! wincheck {
+  ($funcall:expr) => {{
+    let rc = unsafe { $funcall };
+    if rc == 0 {
+      Err(OpError::from(std::io::Error::last_os_error()))?;
+    }
+    rc
+  }};
+}
+
+#[derive(Deserialize)]
+struct SetRawArgs {
+  rid: u32,
+  mode: bool,
+}
+
+pub fn op_set_raw(
+  state_: &State,
+  args: Value,
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<JsonOp, OpError> {
+  let args: SetRawArgs = serde_json::from_value(args)?;
+  let rid = args.rid;
+  let is_raw = args.mode;
+
+  // From https://github.com/kkawakam/rustyline/blob/master/src/tty/windows.rs
+  // and https://github.com/kkawakam/rustyline/blob/master/src/tty/unix.rs
+  // and https://github.com/crossterm-rs/crossterm/blob/e35d4d2c1cc4c919e36d242e014af75f6127ab50/src/terminal/sys/windows.rs
+  // Copyright (c) 2015 Katsu Kawakami & Rustyline authors. MIT license.
+  // Copyright (c) 2019 Timon. MIT license.
+  #[cfg(windows)]
+  {
+    use std::os::windows::io::AsRawHandle;
+    use winapi::um::{consoleapi, handleapi};
+
+    let state = state_.borrow_mut();
+    let resource = state.resource_table.get::<StreamResource>(rid);
+    if resource.is_none() {
+      return Err(OpError::bad_resource());
+    }
+
+    // For now, only stdin.
+    let handle = match resource.unwrap() {
+      StreamResource::Stdin(_, _) => std::io::stdin().as_raw_handle(),
+      StreamResource::FsFile(f, _) => {
+        let tokio_file = futures::executor::block_on(f.try_clone())?;
+        let std_file = futures::executor::block_on(tokio_file.into_std());
+        std_file.as_raw_handle()
+      }
+      _ => {
+        return Err(OpError::other("Not supported".to_owned()));
+      }
+    };
+
+    if handle == handleapi::INVALID_HANDLE_VALUE {
+      return Err(OpError::from(std::io::Error::last_os_error()));
+    } else if handle.is_null() {
+      return Err(OpError::other("null handle".to_owned()));
+    }
+    let mut original_mode: DWORD = 0;
+    wincheck!(consoleapi::GetConsoleMode(handle, &mut original_mode));
+    let new_mode = if is_raw {
+      original_mode & !RAW_MODE_MASK
+    } else {
+      original_mode | RAW_MODE_MASK
+    };
+    wincheck!(consoleapi::SetConsoleMode(handle, new_mode));
+
+    Ok(JsonOp::Sync(json!({})))
+  }
+  #[cfg(unix)]
+  {
+    use std::os::unix::io::AsRawFd;
+
+    let mut state = state_.borrow_mut();
+    let resource = state.resource_table.get_mut::<StreamResource>(rid);
+    if resource.is_none() {
+      return Err(OpError::bad_resource());
+    }
+
+    if is_raw {
+      let (raw_fd, maybe_tty_mode) = match resource.unwrap() {
+        StreamResource::Stdin(_, ref mut metadata) => {
+          (std::io::stdin().as_raw_fd(), &mut metadata.mode)
+        }
+        StreamResource::FsFile(f, ref mut metadata) => {
+          let tokio_file = futures::executor::block_on(f.try_clone())?;
+          let std_file = futures::executor::block_on(tokio_file.into_std());
+          (std_file.as_raw_fd(), &mut metadata.tty.mode)
+        }
+        _ => {
+          return Err(OpError::other("Not supported".to_owned()));
+        }
+      };
+
+      if maybe_tty_mode.is_some() {
+        // Already raw. Skip.
+        return Ok(JsonOp::Sync(json!({})));
+      }
+
+      let original_mode = termios::tcgetattr(raw_fd)?;
+      let mut raw = original_mode.clone();
+      // Save original mode.
+      maybe_tty_mode.replace(original_mode);
+
+      raw.input_flags &= !(termios::InputFlags::BRKINT
+        | termios::InputFlags::ICRNL
+        | termios::InputFlags::INPCK
+        | termios::InputFlags::ISTRIP
+        | termios::InputFlags::IXON);
+
+      raw.control_flags |= termios::ControlFlags::CS8;
+
+      raw.local_flags &= !(termios::LocalFlags::ECHO
+        | termios::LocalFlags::ICANON
+        | termios::LocalFlags::IEXTEN
+        | termios::LocalFlags::ISIG);
+      raw.control_chars[termios::SpecialCharacterIndices::VMIN as usize] = 1;
+      raw.control_chars[termios::SpecialCharacterIndices::VTIME as usize] = 0;
+      termios::tcsetattr(raw_fd, termios::SetArg::TCSADRAIN, &raw)?;
+      Ok(JsonOp::Sync(json!({})))
+    } else {
+      // Try restore saved mode.
+      let (raw_fd, maybe_tty_mode) = match resource.unwrap() {
+        StreamResource::Stdin(_, ref mut metadata) => {
+          (std::io::stdin().as_raw_fd(), &mut metadata.mode)
+        }
+        StreamResource::FsFile(f, ref mut metadata) => {
+          let tokio_file = futures::executor::block_on(f.try_clone())?;
+          let std_file = futures::executor::block_on(tokio_file.into_std());
+          (std_file.as_raw_fd(), &mut metadata.tty.mode)
+        }
+        _ => {
+          return Err(OpError::other("Not supported".to_owned()));
+        }
+      };
+
+      if let Some(mode) = maybe_tty_mode.take() {
+        termios::tcsetattr(raw_fd, termios::SetArg::TCSADRAIN, &mode)?;
+      }
+
+      Ok(JsonOp::Sync(json!({})))
+    }
+  }
+}
+
+#[derive(Deserialize)]
+struct IsattyArgs {
+  rid: u32,
+}
+
+pub fn op_isatty(
+  state_: &State,
+  args: Value,
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<JsonOp, OpError> {
+  let args: IsattyArgs = serde_json::from_value(args)?;
+  let rid = args.rid;
+
+  let state = state_.borrow_mut();
+  if !state.resource_table.has(rid) {
+    return Err(OpError::bad_resource());
+  }
+
+  let resource = state.resource_table.get::<StreamResource>(rid);
+  if resource.is_none() {
+    return Ok(JsonOp::Sync(json!(false)));
+  }
+
+  match resource.unwrap() {
+    StreamResource::Stdin(_, _) => {
+      Ok(JsonOp::Sync(json!(atty::is(atty::Stream::Stdin))))
+    }
+    StreamResource::Stdout(_) => {
+      Ok(JsonOp::Sync(json!(atty::is(atty::Stream::Stdout))))
+    }
+    StreamResource::Stderr(_) => {
+      Ok(JsonOp::Sync(json!(atty::is(atty::Stream::Stderr))))
+    }
+    StreamResource::FsFile(f, _) => {
+      let tokio_file = futures::executor::block_on(f.try_clone())?;
+      let std_file = futures::executor::block_on(tokio_file.into_std());
+      #[cfg(windows)]
+      {
+        use winapi::um::consoleapi;
+
+        let handle = get_windows_handle(&std_file)?;
+        let mut test_mode: DWORD = 0;
+        // If I cannot get mode out of console, it is not a console.
+        let result =
+          unsafe { consoleapi::GetConsoleMode(handle, &mut test_mode) != 0 };
+        Ok(JsonOp::Sync(json!(result)))
+      }
+      #[cfg(unix)]
+      {
+        use std::os::unix::io::AsRawFd;
+        let raw_fd = std_file.as_raw_fd();
+        let result = unsafe { libc::isatty(raw_fd as libc::c_int) == 1 };
+        Ok(JsonOp::Sync(json!(result)))
+      }
+    }
+    _ => Ok(JsonOp::Sync(json!(false))),
+  }
+}
diff --git a/cli/tests/integration_tests.rs b/cli/tests/integration_tests.rs
index 29c4ac1d05..7fd531c298 100644
--- a/cli/tests/integration_tests.rs
+++ b/cli/tests/integration_tests.rs
@@ -1,8 +1,61 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 #[macro_use]
 extern crate lazy_static;
+#[cfg(unix)]
+extern crate nix;
+#[cfg(unix)]
+extern crate pty;
 extern crate tempfile;
 
+#[cfg(unix)]
+#[test]
+pub fn test_raw_tty() {
+  use pty::fork::*;
+  use std::io::{Read, Write};
+
+  let fork = Fork::from_ptmx().unwrap();
+
+  if let Ok(mut master) = fork.is_parent() {
+    let mut obytes: [u8; 100] = [0; 100];
+    let mut nread = master.read(&mut obytes).unwrap();
+    assert_eq!(String::from_utf8_lossy(&obytes[0..nread]), "S");
+    master.write_all(b"a").unwrap();
+    nread = master.read(&mut obytes).unwrap();
+    assert_eq!(String::from_utf8_lossy(&obytes[0..nread]), "A");
+    master.write_all(b"b").unwrap();
+    nread = master.read(&mut obytes).unwrap();
+    assert_eq!(String::from_utf8_lossy(&obytes[0..nread]), "B");
+    master.write_all(b"c").unwrap();
+    nread = master.read(&mut obytes).unwrap();
+    assert_eq!(String::from_utf8_lossy(&obytes[0..nread]), "C");
+  } else {
+    use deno::test_util::*;
+    use nix::sys::termios;
+    use std::os::unix::io::AsRawFd;
+    use std::process::*;
+    use tempfile::TempDir;
+
+    // Turn off echo such that parent is reading works properly.
+    let stdin_fd = std::io::stdin().as_raw_fd();
+    let mut t = termios::tcgetattr(stdin_fd).unwrap();
+    t.local_flags.remove(termios::LocalFlags::ECHO);
+    termios::tcsetattr(stdin_fd, termios::SetArg::TCSANOW, &t).unwrap();
+
+    let deno_dir = TempDir::new().expect("tempdir fail");
+    let mut child = Command::new(deno_exe_path())
+      .env("DENO_DIR", deno_dir.path())
+      .current_dir(util::root_path())
+      .arg("run")
+      .arg("cli/tests/raw_mode.ts")
+      .stdin(Stdio::inherit())
+      .stdout(Stdio::inherit())
+      .stderr(Stdio::null())
+      .spawn()
+      .expect("Failed to spawn script");
+    child.wait().unwrap();
+  }
+}
+
 #[test]
 fn test_pattern_match() {
   assert!(util::pattern_match("foo[BAR]baz", "foobarbaz", "[BAR]"));
diff --git a/cli/tests/raw_mode.ts b/cli/tests/raw_mode.ts
new file mode 100644
index 0000000000..125601b2b5
--- /dev/null
+++ b/cli/tests/raw_mode.ts
@@ -0,0 +1,18 @@
+Deno.setRaw(0, true);
+Deno.setRaw(0, true); // Can be called multiple times
+
+Deno.stdout.writeSync(new TextEncoder().encode("S"));
+
+const buf = new Uint8Array(3);
+for (let i = 0; i < 3; i++) {
+  const nread = await Deno.stdin.read(buf);
+  if (nread === Deno.EOF) {
+    break;
+  } else {
+    const data = new TextDecoder().decode(buf.subarray(0, nread));
+    Deno.stdout.writeSync(new TextEncoder().encode(data.toUpperCase()));
+  }
+}
+
+Deno.setRaw(0, false); // restores old mode.
+Deno.setRaw(0, false); // Can be safely called multiple times
diff --git a/cli/worker.rs b/cli/worker.rs
index a4a35dfaab..b619b2a67b 100644
--- a/cli/worker.rs
+++ b/cli/worker.rs
@@ -219,6 +219,7 @@ impl MainWorker {
       ops::resources::init(isolate, &state);
       ops::signal::init(isolate, &state);
       ops::timers::init(isolate, &state);
+      ops::tty::init(isolate, &state);
       ops::worker_host::init(isolate, &state);
       ops::web_worker::init(isolate, &state, &worker.internal_channels.sender);
     }
diff --git a/core/resources.rs b/core/resources.rs
index 51b66c4bc5..a5563bed35 100644
--- a/core/resources.rs
+++ b/core/resources.rs
@@ -26,6 +26,10 @@ pub struct ResourceTable {
 }
 
 impl ResourceTable {
+  pub fn has(&self, rid: ResourceId) -> bool {
+    self.map.contains_key(&rid)
+  }
+
   pub fn get<T: Resource>(&self, rid: ResourceId) -> Option<&T> {
     if let Some((_name, resource)) = self.map.get(&rid) {
       return resource.downcast_ref::<T>();