.

89 files changed, 293 insertions, 102 deletions

diff --git a/README.md b/README.md
index 07fa7f2c..bf8a89d8 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Here's the Mu computer running [Conway's Game of Life](https://en.wikipedia.org/
 ```sh
 git clone https://github.com/akkartik/mu
 cd mu
-./translate life.mu  # emit a bootable code.img
+./translate apps/life.mu  # emit a bootable code.img
 qemu-system-i386 code.img
 ```
 
@@ -94,7 +94,7 @@ Mu programs build natively either on Linux or on Windows using [WSL 2](https://d
 For Macs and other Unix-like systems, use the (much slower) emulator:
 
 ```sh
-./translate_emulated ex2.mu  # ~2 mins to emit code.img
+./translate_emulated apps/ex2.mu  # ~2 mins to emit code.img
 ```
 
 Mu programs can be written for two very different environments:
diff --git a/boot0.hex b/apps/boot0.hex
index 4753451e..929d2fd9 100644
--- a/boot0.hex
+++ b/apps/boot0.hex
@@ -11,7 +11,7 @@
 # To convert to a disk image, first prepare a realistically sized disk image:
 #   dd if=/dev/zero of=code.img count=20160  # 512-byte sectors, so 10MB
 # Now fill in sectors:
-#   bootstrap/bootstrap run hex < boot0.hex > boot.bin
+#   linux/bootstrap/bootstrap run linux/hex < apps/boot0.hex > boot.bin
 #   dd if=boot.bin of=code.img conv=notrunc
 # To run:
 #   qemu-system-i386 code.img
diff --git a/colors.mu b/apps/colors.mu
index 90f33454..78e58838 100644
--- a/colors.mu
+++ b/apps/colors.mu
@@ -2,7 +2,7 @@
 # If we did this rigorously we'd need to implement cosines. So we won't.
 #
 # To build:
-#   $ ./translate colors.mu
+#   $ ./translate apps/colors.mu
 #
 # Example session:
 #   $ qemu-system-i386 code.img
diff --git a/apps/ex1.mu b/apps/ex1.mu
new file mode 100644
index 00000000..a96bed07
--- /dev/null
+++ b/apps/ex1.mu
@@ -0,0 +1,14 @@
+# The simplest possible bare-metal program.
+#
+# To build a disk image:
+#   ./translate apps/ex1.mu        # emits code.img
+# To run:
+#   qemu-system-i386 code.img
+# Or:
+#   bochs -f bochsrc               # bochsrc loads code.img
+#
+# Expected output: blank screen with no errors
+
+fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
+  loop
+}
diff --git a/ex10.mu b/apps/ex10.mu
index 858c4a25..05198738 100644
--- a/ex10.mu
+++ b/apps/ex10.mu
@@ -1,7 +1,7 @@
 # Demo of mouse support.
 #
 # To build a disk image:
-#   ./translate ex10.mu            # emits code.img
+#   ./translate apps/ex10.mu       # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/apps/ex10.mu. b/apps/ex10.mu.
new file mode 100644
index 00000000..35fea653
--- /dev/null
+++ b/apps/ex10.mu.
@@ -0,0 +1,176 @@
+# Demo of mouse support.
+#
+# To build a disk image:
+#   ./translate ex10.mu            # emits disk.img
+# To run:
+#   qemu-system-i386 disk.img
+# Or:
+#   bochs -f bochsrc               # bochsrc loads disk.img
+
+fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
+#?   var x/esi: int <- copy 0x200
+#?   var y/edi: int <- copy 0x180
+#?   render-grid x, y
+  $main:event-loop: {
+    # read deltas from mouse
+    var dx/eax: int <- copy 0
+    var dy/ecx: int <- copy 0
+    dx, dy <- read-mouse-event
+    # loop if deltas are both 0
+    {
+      compare dx, 0
+      break-if-!=
+      compare dy, 0
+      break-if-!=
+      loop $main:event-loop
+    }
+    # render unclamped deltas
+#?     render-grid x, y
+    draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen screen, dx, 7/fg, 0/bg
+    draw-text-wrapping-right-then-down-from-cursor-over-full-screen screen, " ", 7/fg, 0/bg
+    draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen screen, dy, 7/fg, 0/bg
+    move-cursor-to-left-margin-of-next-line screen
+#?     {
+#?       var dummy1/eax: int <- copy 0
+#?       var dummy2/ecx: int <- copy 0
+#?       dummy1, dummy2 <- draw-text-wrapping-right-then-down-over-full-screen screen, "         ", 0/x, 0x10/y, 0x31/fg, 0/bg
+#?     }
+#?     {
+#?       var ephemeral-dx/eax: int <- copy dx
+#?       var dummy/ecx: int <- copy 0
+#?       ephemeral-dx, dummy <- draw-int32-decimal-wrapping-right-then-down-over-full-screen screen, ephemeral-dx, 0/x, 0x10/y, 0x31/fg, 0/bg
+#?     }
+#?     {
+#?       var dummy/eax: int <- copy 0
+#?       var ephemeral-dy/ecx: int <- copy dy
+#?       dummy, ephemeral-dy <- draw-int32-decimal-wrapping-right-then-down-over-full-screen screen, ephemeral-dy, 5/x, 0x10/y, 0x31/fg, 0/bg
+#?     }
+#?     # clamp deltas
+#?     $clamp-dx: {
+#?       compare dx, -0xa
+#?       {
+#?         break-if->
+#?         dx <- copy -0xa
+#?         break $clamp-dx
+#?       }
+#?       compare dx, 0xa
+#?       {
+#?         break-if-<
+#?         dx <- copy 0xa
+#?         break $clamp-dx
+#?       }
+#?       dx <- copy 0
+#?     }
+#?     $clamp-dy: {
+#?       compare dy, -0xa
+#?       {
+#?         break-if->
+#?         dy <- copy -0xa
+#?         break $clamp-dy
+#?       }
+#?       compare dy, 0xa
+#?       {
+#?         break-if-<
+#?         dy <- copy 0xa
+#?         break $clamp-dy
+#?       }
+#?       dy <- copy 0
+#?     }
+#?     # render clamped deltas
+#?     {
+#?       var dummy1/eax: int <- copy 0
+#?       var dummy2/ecx: int <- copy 0
+#?       dummy1, dummy2 <- draw-text-wrapping-right-then-down-over-full-screen screen, "         ", 0/x, 0x20/y, 0x31/fg, 0/bg
+#?     }
+#?     {
+#?       var save-dx/eax: int <- copy dx
+#?       var dummy/ecx: int <- copy 0
+#?       save-dx, dummy <- draw-int32-decimal-wrapping-right-then-down-over-full-screen screen, save-dx, 0/x, 0x20/y, 0x31/fg, 0/bg
+#?     }
+#?     {
+#?       var dummy/eax: int <- copy 0
+#?       var save-dy/ecx: int <- copy dy
+#?       dummy, save-dy <- draw-int32-decimal-wrapping-right-then-down-over-full-screen screen, save-dy, 5/x, 0x20/y, 0x31/fg, 0/bg
+#?     }
+#?     # loop if deltas are both 0
+#?     {
+#?       compare dx, 0
+#?       break-if-!=
+#?       compare dy, 0
+#?       break-if-!=
+#?       loop $main:event-loop
+#?     }
+#?     # accumulate deltas and clamp result within screen bounds
+#?     x <- add dx
+#?     compare x, 0
+#?     {
+#?       break-if->=
+#?       x <- copy 0
+#?     }
+#?     compare x, 0x400
+#?     {
+#?       break-if-<
+#?       x <- copy 0x3ff
+#?     }
+#?     y <- subtract dy  # mouse y coordinates are reverse compared to screen
+#?     compare y, 0
+#?     {
+#?       break-if->=
+#?       y <- copy 0
+#?     }
+#?     compare y, 0x300
+#?     {
+#?       break-if-<
+#?       y <- copy 0x2ff
+#?     }
+    loop
+  }
+}
+
+#? fn render-grid curr-x: int, curr-y: int {
+#?   and-with curr-x, 0xfffffffc
+#?   and-with curr-y, 0xfffffffc
+#?   var y/eax: int <- copy 0
+#?   {
+#?     compare y, 0x300/screen-height=768
+#?     break-if->=
+#?     var x/edx: int <- copy 0
+#?     {
+#?       compare x, 0x400/screen-width=1024
+#?       break-if->=
+#?       var color/ecx: int <- copy 0
+#?       # set color if either x or y is divisible by 4
+#?       var tmp/ebx: int <- copy y
+#?       tmp <- and 3
+#?       compare tmp, 0
+#?       {
+#?         break-if-!=
+#?         color <- copy 3
+#?       }
+#?       tmp <- copy x
+#?       tmp <- and 3
+#?       compare tmp, 0
+#?       {
+#?         break-if-!=
+#?         color <- copy 3
+#?       }
+#?       # highlight color if x and y match curr-x and curr-y (quantized)
+#?       {
+#?         var xq/edx: int <- copy x
+#?         xq <- and 0xfffffffc
+#?         var yq/eax: int <- copy y
+#?         yq <- and 0xfffffffc
+#?         compare xq, curr-x
+#?         break-if-!=
+#?         compare yq, curr-y
+#?         break-if-!=
+#?         color <- copy 0xc
+#?       }
+#?       pixel-on-real-screen x, y, color
+#?       x <- increment
+#?       loop
+#?     }
+#?     y <- increment
+#?     loop
+#?   }
+#? }
diff --git a/ex11.mu b/apps/ex11.mu
index c52deb2f..6b967724 100644
--- a/ex11.mu
+++ b/apps/ex11.mu
@@ -1,7 +1,7 @@
 # Demo of an interactive app: controlling a Bezier curve on screen
 #
 # To build a disk image:
-#   ./translate ex11.mu            # emits code.img
+#   ./translate apps/ex11.mu       # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex12.mu b/apps/ex12.mu
index fe97daa9..79c259b8 100644
--- a/ex12.mu
+++ b/apps/ex12.mu
@@ -1,7 +1,7 @@
 # Checking the timer.
 #
 # To build a disk image:
-#   ./translate ex12.mu            # emits code.img
+#   ./translate apps/ex12.mu       # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex2.mu b/apps/ex2.mu
index 0d301508..be66d883 100644
--- a/ex2.mu
+++ b/apps/ex2.mu
@@ -1,7 +1,7 @@
 # Test out the video mode by filling in the screen with pixels.
 #
 # To build a disk image:
-#   ./translate ex2.mu             # emits code.img
+#   ./translate apps/ex2.mu        # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex3.mu b/apps/ex3.mu
index b90af18b..155457c6 100644
--- a/ex3.mu
+++ b/apps/ex3.mu
@@ -2,7 +2,7 @@
 # and in raster order.
 #
 # To build a disk image:
-#   ./translate ex3.mu             # emits code.img
+#   ./translate apps/ex3.mu        # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex4.mu b/apps/ex4.mu
index ec43c3e0..9c3e28ee 100644
--- a/ex4.mu
+++ b/apps/ex4.mu
@@ -1,7 +1,7 @@
 # Draw a character using the built-in font (GNU unifont)
 #
 # To build a disk image:
-#   ./translate ex4.mu             # emits code.img
+#   ./translate apps/ex4.mu        # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex5.mu b/apps/ex5.mu
index 7a915ea7..07e8bc1a 100644
--- a/ex5.mu
+++ b/apps/ex5.mu
@@ -2,7 +2,7 @@
 # Also demonstrates bounds-checking _before_ drawing.
 #
 # To build a disk image:
-#   ./translate ex5.mu             # emits code.img
+#   ./translate apps/ex5.mu        # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex6.mu b/apps/ex6.mu
index cae98e36..fbad3c13 100644
--- a/ex6.mu
+++ b/apps/ex6.mu
@@ -1,7 +1,7 @@
 # Drawing ASCII text incrementally.
 #
 # To build a disk image:
-#   ./translate ex6.mu             # emits code.img
+#   ./translate apps/ex6.mu        # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex7.mu b/apps/ex7.mu
index 4ddd754a..bd0afd20 100644
--- a/ex7.mu
+++ b/apps/ex7.mu
@@ -1,7 +1,7 @@
 # Cursor-based motions.
 #
 # To build a disk image:
-#   ./translate ex7.mu             # emits code.img
+#   ./translate apps/ex7.mu        # emits code.img
 # To run:
 #   qemu-system-i386 code.img
 # Or:
diff --git a/ex8.mu b/apps/ex8.mu
index 64c0c24f..c5e695ed 100644
--- a/ex8.mu
+++ b/apps/ex8.mu
@@ -1,7 +1,7 @@
 # Demo of floating-point support.
 #
 # To build a disk image:
-#   ./translate ex8.mu             # emits code.img
+#   ./translate apps/ex8.mu        # emits code.img
 # To run:
 #   bochs -f bochsrc               # bochsrc loads code.img
 # Set a breakpoint at 0x7c00 and start stepping.
diff --git a/ex9.mu b/apps/ex9.mu
index e0767d9c..30853c69 100644
--- a/ex9.mu
+++ b/apps/ex9.mu
@@ -2,7 +2,7 @@
 #
 # Steps for trying it out:
 #   1. Translate this example into a disk image code.img.
-#       ./translate ex9.mu
+#       ./translate apps/ex9.mu
 #   2. Build a second disk image data.img containing some text.
 #       dd if=/dev/zero of=data.img count=20160
 #       echo 'abc def ghi' |dd of=data.img conv=notrunc
diff --git a/hest-life.mu b/apps/hest-life.mu
index b9358587..62f2d945 100644
--- a/hest-life.mu
+++ b/apps/hest-life.mu
@@ -3,14 +3,14 @@
 #   https://ivanish.ca/hest-podcast
 #
 # To build:
-#   $ ./translate hest-life.mu
+#   $ ./translate apps/hest-life.mu
 # I run it on my 2.5GHz Linux laptop like this:
-#   $ qemu-system-i386 -enable-kvm code.img
+#   $ qemu-system-i386 code.img
 #
 # If things seem too fast or too slow on your computer, adjust the loop bounds
 # in the function `linger` at the bottom. Its value will depend on how you
-# accelerate Qemu. Mu will eventually get a clock to obviate the need for this
-# tuning.
+# accelerate Qemu (`-accel help`). Mu will eventually get a clock to obviate
+# the need for this tuning.
 #
 # Keyboard shortcuts:
 #   space: pause/resume
diff --git a/img.mu b/apps/img.mu
index 8177ae6b..65b773c5 100644
--- a/img.mu
+++ b/apps/img.mu
@@ -1,7 +1,7 @@
 # load an image from disk and display it on screen
 #
 # To build:
-#   $ ./translate img.mu                            # generates code.img
+#   $ ./translate apps/img.mu                       # generates code.img
 # Load a pbm, pgm or ppm image (no more than 255 levels) in the data disk
 #   $ dd if=/dev/zero of=data.img count=20160
 #   $ dd if=x.pbm of=data.img conv=notrunc
diff --git a/life.mu b/apps/life.mu
index b3947434..a65347bf 100644
--- a/life.mu
+++ b/apps/life.mu
@@ -1,7 +1,7 @@
 # Conway's Game of Life
 #
 # To build:
-#   $ ./translate life.mu
+#   $ ./translate apps/life.mu
 # To run:
 #   $ qemu-system-i386 code.img
 
diff --git a/mandelbrot-fixed.mu b/apps/mandelbrot-fixed.mu
index b633cfe5..fc33aae1 100644
--- a/mandelbrot-fixed.mu
+++ b/apps/mandelbrot-fixed.mu
@@ -4,9 +4,9 @@
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
 # Build on Linux:
-#   $ ./translate mandelbrot-fixed.mu
+#   $ ./translate apps/mandelbrot-fixed.mu
 # Build on other platforms (slow):
-#   $ ./translate_emulated mandelbrot-fixed.mu
+#   $ ./translate_emulated apps/mandelbrot-fixed.mu
 # Run:
 #   $ qemu-system-i386 code.img
 
diff --git a/mandelbrot-silhouette.mu b/apps/mandelbrot-silhouette.mu
index fa1abaff..0d9a137c 100644
--- a/mandelbrot-silhouette.mu
+++ b/apps/mandelbrot-silhouette.mu
@@ -4,9 +4,9 @@
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
 # Build on Linux:
-#   $ ./translate mandelbrot.mu
+#   $ ./translate apps/mandelbrot.mu
 # Build on other platforms (slow):
-#   $ ./translate_emulated mandelbrot.mu
+#   $ ./translate_emulated apps/mandelbrot.mu
 # Run:
 #   $ qemu-system-i386 code.img
 
diff --git a/mandelbrot.mu b/apps/mandelbrot.mu
index 278fafc2..218fd4fa 100644
--- a/mandelbrot.mu
+++ b/apps/mandelbrot.mu
@@ -4,9 +4,9 @@
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
 # Build on Linux:
-#   $ ./translate mandelbrot.mu
+#   $ ./translate apps/mandelbrot.mu
 # Build on other platforms (slow):
-#   $ ./translate_emulated mandelbrot.mu
+#   $ ./translate_emulated apps/mandelbrot.mu
 # Run:
 #   $ qemu-system-i386 code.img
 
diff --git a/rpn.mu b/apps/rpn.mu
index a634c791..1f432365 100644
--- a/rpn.mu
+++ b/apps/rpn.mu
@@ -4,7 +4,7 @@
 #   Division not implemented yet.
 #
 # To build:
-#   $ ./translate rpn.mu
+#   $ ./translate apps/rpn.mu
 #
 # Example session:
 #   $ qemu-system-i386 code.img
diff --git a/ex1.mu b/ex1.mu
deleted file mode 100644
index 0b379f60..00000000
--- a/ex1.mu
+++ /dev/null
@@ -1,3 +0,0 @@
-fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
-  loop
-}
diff --git a/linux/README.md b/linux/README.md
index 8b81a386..0b8bc6fb 100644
--- a/linux/README.md
+++ b/linux/README.md
@@ -3,7 +3,7 @@ kernel. To run programs under this directory, you must first `cd` into it.
 
   ```sh
   $ cd linux/
-  $ ./translate hello.mu      # generates a.elf
+  $ ./translate apps/hello.mu      # generates a.elf
   $ ./a.elf
   Hello world!
   ```
@@ -22,11 +22,11 @@ Some programs to try out:
 
 * `browse`: [A text-mode browser for a tiny subset of Markdown](https://mastodon.social/@akkartik/104845344081779025).
 
-* `ex*`: small stand-alone examples that don't need any of the shared code at
+* `apps/ex*`: small stand-alone examples that don't need any of the shared code at
   the top-level. They each have a simple pedagogical goal. Read these first.
 
-* `factorial*`: A simple program to compute factorials in 5 versions, showing
-  all the different syntax sugars and what they expand to.
+* `apps/factorial*`: A simple program to compute factorials in 5 versions,
+  showing all the different syntax sugars and what they expand to.
 
 The Mu compiler toolchain is also here in the following phases:
 
diff --git a/linux/advent2017/1a.mu b/linux/apps/advent2017/1a.mu
index 2f639080..aae12989 100644
--- a/linux/advent2017/1a.mu
+++ b/linux/apps/advent2017/1a.mu
@@ -7,7 +7,7 @@
 # To build on Linux:
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu/linux
-#   $ ./translate advent2017/1a.mu            # emits a.elf
+#   $ ./translate apps/advent2017/1a.mu            # emits a.elf
 # To run on Linux:
 #   Download https://adventofcode.com/2017/day/1/input
 #   $ ./a.elf < input
diff --git a/linux/advent2020/1a.mu b/linux/apps/advent2020/1a.mu
index 886329f1..da71340a 100644
--- a/linux/advent2020/1a.mu
+++ b/linux/apps/advent2020/1a.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/1a.mu
+#   $ ./translate apps/advent2020/1a.mu
 #   $ ./a.elf < input
 #   found
 #   1353 667
diff --git a/linux/advent2020/1b.mu b/linux/apps/advent2020/1b.mu
index bfdbe47c..a99709b8 100644
--- a/linux/advent2020/1b.mu
+++ b/linux/apps/advent2020/1b.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/1b.mu
+#   $ ./translate apps/advent2020/1b.mu
 #   $ ./a.elf < input
 #   found
 #   143 407 1470
diff --git a/linux/advent2020/2a.mu b/linux/apps/advent2020/2a.mu
index ce678eb8..44d50d46 100644
--- a/linux/advent2020/2a.mu
+++ b/linux/apps/advent2020/2a.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/2a.mu
+#   $ ./translate apps/advent2020/2a.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/2b.mu b/linux/apps/advent2020/2b.mu
index 121e9dfa..d0d23998 100644
--- a/linux/advent2020/2b.mu
+++ b/linux/apps/advent2020/2b.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/2b.mu
+#   $ ./translate apps/advent2020/2b.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/3a.mu b/linux/apps/advent2020/3a.mu
index d2dfc15e..6f95ddf1 100644
--- a/linux/advent2020/3a.mu
+++ b/linux/apps/advent2020/3a.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/3a.mu
+#   $ ./translate apps/advent2020/3a.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/3b.mu b/linux/apps/advent2020/3b.mu
index 7db91eea..8a4f442d 100644
--- a/linux/advent2020/3b.mu
+++ b/linux/apps/advent2020/3b.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/3a.mu
+#   $ ./translate apps/advent2020/3a.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/4a.mu b/linux/apps/advent2020/4a.mu
index 1b16712d..2efe475a 100644
--- a/linux/advent2020/4a.mu
+++ b/linux/apps/advent2020/4a.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/4a.mu
+#   $ ./translate apps/advent2020/4a.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/4b.mu b/linux/apps/advent2020/4b.mu
index 2dc6c6a2..e92e96e4 100644
--- a/linux/advent2020/4b.mu
+++ b/linux/apps/advent2020/4b.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/4b.mu
+#   $ ./translate apps/advent2020/4b.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/5a.mu b/linux/apps/advent2020/5a.mu
index 19d342c4..34e2e113 100644
--- a/linux/advent2020/5a.mu
+++ b/linux/apps/advent2020/5a.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/5a.mu
+#   $ ./translate apps/advent2020/5a.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/5b.mu b/linux/apps/advent2020/5b.mu
index e6a3520f..197ea885 100644
--- a/linux/advent2020/5b.mu
+++ b/linux/apps/advent2020/5b.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate advent2020/5b.mu
+#   $ ./translate apps/advent2020/5b.mu
 #   $ ./a.elf < input
 #
 # You'll need to register to download the 'input' file for yourself.
diff --git a/linux/advent2020/vimrc.vim b/linux/apps/advent2020/vimrc.vim
index 348fe364..348fe364 100644
--- a/linux/advent2020/vimrc.vim
+++ b/linux/apps/advent2020/vimrc.vim
diff --git a/linux/arith.mu b/linux/apps/arith.mu
index 5a9d5032..4393a34c 100644
--- a/linux/arith.mu
+++ b/linux/apps/arith.mu
@@ -7,7 +7,7 @@
 #   No division yet.
 #
 # To build:
-#   $ ./translate arith.mu
+#   $ ./translate apps/arith.mu
 #
 # Example session:
 #   $ ./a.elf
diff --git a/linux/crenshaw2-1.subx b/linux/apps/crenshaw2-1.subx
index ade0399a..73c0f16e 100644
--- a/linux/crenshaw2-1.subx
+++ b/linux/apps/crenshaw2-1.subx
@@ -3,7 +3,7 @@
 # except that we support hex digits.
 #
 # To run:
-#   $ bootstrap/bootstrap translate [01]*.subx crenshaw2-1.subx -o crenshaw2-1
+#   $ bootstrap/bootstrap translate [01]*.subx apps/crenshaw2-1.subx -o crenshaw2-1
 #   $ echo '3'  |bootstrap/bootstrap run crenshaw2-1
 # Expected output:
 #   # syscall(exit, 3)
diff --git a/linux/crenshaw2-1b.subx b/linux/apps/crenshaw2-1b.subx
index d5b8194e..033c69c5 100644
--- a/linux/crenshaw2-1b.subx
+++ b/linux/apps/crenshaw2-1b.subx
@@ -3,7 +3,7 @@
 # except that we support hex numbers of multiple digits.
 #
 # To run:
-#   $ bootstrap/bootstrap translate [01]*.subx crenshaw2-1b.subx -o crenshaw2-1b
+#   $ bootstrap/bootstrap translate [01]*.subx apps/crenshaw2-1b.subx -o crenshaw2-1b
 #   $ echo '1a'  |bootstrap/bootstrap run crenshaw2-1b
 # Expected output:
 #   # syscall(exit, 1a)
diff --git a/linux/ex1.mu b/linux/apps/ex1.mu
index fbf38d0c..36304803 100644
--- a/linux/ex1.mu
+++ b/linux/apps/ex1.mu
@@ -1,8 +1,10 @@
 # First example: return the answer to the Ultimate Question of Life, the
 # Universe, and Everything.
 #
+# Same as https://www.muppetlabs.com/~breadbox/software/tiny/teensy.html
+#
 # To run:
-#   $ ./translate ex1.mu
+#   $ ./translate apps/ex1.mu
 #   $ ./a.elf
 # Expected result:
 #   $ echo $?
diff --git a/linux/apps/ex1.subx b/linux/apps/ex1.subx
new file mode 100644
index 00000000..0406dbe8
--- /dev/null
+++ b/linux/apps/ex1.subx
@@ -0,0 +1,20 @@
+# First example: return the answer to the Ultimate Question of Life, the
+# Universe, and Everything.
+#
+# Same as https://www.muppetlabs.com/~breadbox/software/tiny/teensy.html
+#
+# To run:
+#   $ bootstrap/bootstrap translate apps/ex1.subx -o ex1
+#   $ bootstrap/bootstrap run ex1
+# Expected result:
+#   $ echo $?
+#   42
+
+== code
+
+Entry:
+# exit(42)
+bb/copy-to-ebx  0x2a/imm32  # 42 in hex
+e8/call  syscall_exit/disp32
+
+# . . vim:nowrap:textwidth=0
diff --git a/linux/ex10.subx b/linux/apps/ex10.subx
index 2be53012..c4ce7e2d 100644
--- a/linux/ex10.subx
+++ b/linux/apps/ex10.subx
@@ -1,7 +1,7 @@
 # String comparison: return 1 iff the two args passed in at the commandline are equal.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex10.subx -o ex10
+#   $ bootstrap/bootstrap translate apps/ex10.subx -o ex10
 #   $ bootstrap/bootstrap run ex10 abc abd
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex11.subx b/linux/apps/ex11.subx
index d8596b8e..0ec5cc1a 100644
--- a/linux/ex11.subx
+++ b/linux/apps/ex11.subx
@@ -6,7 +6,7 @@
 # a null-terminated 'kernel string' with a size-prefixed 'SubX string'.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex11.subx -o ex11
+#   $ bootstrap/bootstrap translate apps/ex11.subx -o ex11
 #   $ bootstrap/bootstrap run ex11  # runs a series of tests
 #   ......  # all tests pass
 #
diff --git a/linux/ex12.subx b/linux/apps/ex12.subx
index 4f1617a7..476d8cda 100644
--- a/linux/ex12.subx
+++ b/linux/apps/ex12.subx
@@ -2,7 +2,7 @@
 # Create a new segment using mmap, save the address, write to it.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex12.subx -o ex12
+#   $ bootstrap/bootstrap translate apps/ex12.subx -o ex12
 #   $ bootstrap/bootstrap run ex12
 # You shouldn't get a segmentation fault.
 
diff --git a/linux/ex13.subx b/linux/apps/ex13.subx
index 862bf897..56028a05 100644
--- a/linux/ex13.subx
+++ b/linux/apps/ex13.subx
@@ -1,7 +1,7 @@
 # Compare 3 and 3.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex13.subx -o ex13
+#   $ bootstrap/bootstrap translate apps/ex13.subx -o ex13
 #   $ bootstrap/bootstrap run ex13
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex14.subx b/linux/apps/ex14.subx
index 531bae7a..70aa8629 100644
--- a/linux/ex14.subx
+++ b/linux/apps/ex14.subx
@@ -1,7 +1,7 @@
 # Multiply 2 numbers.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex14.subx -o ex14
+#   $ bootstrap/bootstrap translate apps/ex14.subx -o ex14
 #   $ bootstrap/bootstrap run ex14
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex2.mu b/linux/apps/ex2.mu
index 21dee1df..b3b74613 100644
--- a/linux/ex2.mu
+++ b/linux/apps/ex2.mu
@@ -1,7 +1,7 @@
 # Add 3 and 4, and return the result in the exit code.
 #
 # To run:
-#   $ ./translate ex2.mu
+#   $ ./translate apps/ex2.mu
 #   $ ./a.elf
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex2.subx b/linux/apps/ex2.subx
index 5ca39872..40955104 100644
--- a/linux/ex2.subx
+++ b/linux/apps/ex2.subx
@@ -1,7 +1,7 @@
 # Add 3 and 4, and return the result in the exit code.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex2.subx -o ex2
+#   $ bootstrap/bootstrap translate apps/ex2.subx -o ex2
 #   $ bootstrap/bootstrap run ex2
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex3.2.mu b/linux/apps/ex3.2.mu
index 8ca6c992..c5992963 100644
--- a/linux/ex3.2.mu
+++ b/linux/apps/ex3.2.mu
@@ -1,7 +1,7 @@
 # Unnecessarily use an array to sum 1..10
 #
 # To run:
-#   $ ./translate ex3.2.mu
+#   $ ./translate apps/ex3.2.mu
 #   $ ./a.elf
 #   $ echo $?
 #   55
diff --git a/linux/ex3.mu b/linux/apps/ex3.mu
index f96fd099..4ae3e93d 100644
--- a/linux/ex3.mu
+++ b/linux/apps/ex3.mu
@@ -1,7 +1,7 @@
 # Add the first 10 numbers, and return the result in the exit code.
 #
 # To run:
-#   $ ./translate browse.mu
+#   $ ./translate ex3.mu
 #   $ ./a.elf
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex3.subx b/linux/apps/ex3.subx
index 5b74d76c..f4b5fed7 100644
--- a/linux/ex3.subx
+++ b/linux/apps/ex3.subx
@@ -1,7 +1,7 @@
 # Add the first 10 numbers, and return the result in the exit code.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex3.subx -o ex3
+#   $ bootstrap/bootstrap translate apps/ex3.subx -o ex3
 #   $ bootstrap/bootstrap run ex3
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex4.subx b/linux/apps/ex4.subx
index ee78ce7d..3bf62551 100644
--- a/linux/ex4.subx
+++ b/linux/apps/ex4.subx
@@ -1,7 +1,7 @@
 # Read a character from stdin, save it to a global, write it to stdout.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex4.subx -o ex4
+#   $ bootstrap/bootstrap translate apps/ex4.subx -o ex4
 #   $ bootstrap/bootstrap run ex4
 
 == data
diff --git a/linux/ex5.subx b/linux/apps/ex5.subx
index e8957ea7..220a4246 100644
--- a/linux/ex5.subx
+++ b/linux/apps/ex5.subx
@@ -1,7 +1,7 @@
 # Read a character from stdin, save it to a local on the stack, write it to stdout.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex5.subx -o ex5
+#   $ bootstrap/bootstrap translate apps/ex5.subx -o ex5
 #   $ bootstrap/bootstrap run ex5
 
 == code
diff --git a/linux/ex6.subx b/linux/apps/ex6.subx
index 5715e94f..cf6309e6 100644
--- a/linux/ex6.subx
+++ b/linux/apps/ex6.subx
@@ -1,7 +1,7 @@
 # Print out a (global variable) string to stdout.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex6.subx -o ex6
+#   $ bootstrap/bootstrap translate apps/ex6.subx -o ex6
 #   $ bootstrap/bootstrap run ex6
 #   Hello, world!
 
diff --git a/linux/ex7.subx b/linux/apps/ex7.subx
index ad1a50b6..c14fc19d 100644
--- a/linux/ex7.subx
+++ b/linux/apps/ex7.subx
@@ -5,7 +5,7 @@
 # the character read.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex7.subx -o ex7
+#   $ bootstrap/bootstrap translate apps/ex7.subx -o ex7
 #   $ bootstrap/bootstrap run ex7
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex8.subx b/linux/apps/ex8.subx
index 909d1adb..2d962be4 100644
--- a/linux/ex8.subx
+++ b/linux/apps/ex8.subx
@@ -1,7 +1,7 @@
 # Example reading commandline arguments: compute length of first arg.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex8.subx -o ex8
+#   $ bootstrap/bootstrap translate apps/ex8.subx -o ex8
 #   $ bootstrap/bootstrap run ex8 abc de fghi
 # Expected result:
 #   $ echo $?
diff --git a/linux/ex9.subx b/linux/apps/ex9.subx
index cbab3aa9..27520191 100644
--- a/linux/ex9.subx
+++ b/linux/apps/ex9.subx
@@ -4,7 +4,7 @@
 # letter of second arg.
 #
 # To run:
-#   $ bootstrap/bootstrap translate ex9.subx -o ex9
+#   $ bootstrap/bootstrap translate apps/ex9.subx -o ex9
 #   $ bootstrap/bootstrap run ex9 z x
 # Expected result:
 #   $ echo $?
diff --git a/linux/factorial.mu b/linux/apps/factorial.mu
index 7eccc1ec..959d3bc0 100644
--- a/linux/factorial.mu
+++ b/linux/apps/factorial.mu
@@ -1,7 +1,7 @@
 # compute the factorial of 5, and return the result in the exit code
 #
 # To run:
-#   $ ./translate factorial.mu
+#   $ ./translate apps/factorial.mu
 #   $ ./a.elf
 #   $ echo $?
 #   120
diff --git a/linux/factorial.subx b/linux/apps/factorial.subx
index 1bcc0a9d..e36f892d 100644
--- a/linux/factorial.subx
+++ b/linux/apps/factorial.subx
@@ -1,7 +1,7 @@
 ## compute the factorial of 5, and print the result
 #
 # To run:
-#   $ bootstrap/bootstrap translate [01]*.subx factorial.subx -o factorial
+#   $ bootstrap/bootstrap translate [01]*.subx apps/factorial.subx -o factorial
 #   $ bootstrap/bootstrap run factorial
 # Expected result:
 #   $ echo $?
diff --git a/linux/factorial2.subx b/linux/apps/factorial2.subx
index 16af9008..95450b3a 100644
--- a/linux/factorial2.subx
+++ b/linux/apps/factorial2.subx
@@ -4,7 +4,7 @@
 #   rm32 operands
 #
 # To run:
-#   $ ./translate_subx init.linux [01]*.subx factorial.subx -o factorial
+#   $ ./translate_subx init.linux [01]*.subx apps/factorial2.subx -o factorial
 #   $ bootstrap/bootstrap run factorial
 # Expected result:
 #   $ echo $?
diff --git a/linux/factorial3.subx b/linux/apps/factorial3.subx
index 72b76963..deb30377 100644
--- a/linux/factorial3.subx
+++ b/linux/apps/factorial3.subx
@@ -5,7 +5,7 @@
 #   function calls
 #
 # To run:
-#   $ ./translate_subx init.linux [01]*.subx factorial.subx -o factorial
+#   $ ./translate_subx init.linux [01]*.subx apps/factorial3.subx -o factorial
 #   $ bootstrap/bootstrap run factorial
 # Expected result:
 #   $ echo $?
diff --git a/linux/factorial4.subx b/linux/apps/factorial4.subx
index 219fce41..0707cfdd 100644
--- a/linux/factorial4.subx
+++ b/linux/apps/factorial4.subx
@@ -6,7 +6,7 @@
 #   control flow
 #
 # To run:
-#   $ ./translate_subx init.linux [01]*.subx factorial.subx -o factorial
+#   $ ./translate_subx init.linux [01]*.subx apps/factorial4.subx -o factorial
 #   $ bootstrap/bootstrap run factorial
 # Expected result:
 #   $ echo $?
diff --git a/linux/hello.mu b/linux/apps/hello.mu
index ac280b8a..debdf916 100644
--- a/linux/hello.mu
+++ b/linux/apps/hello.mu
@@ -1,7 +1,7 @@
 # Meaningless conventional example.
 #
 # To run:
-#   $ ./translate hello.mu
+#   $ ./translate apps/hello.mu
 #   $ ./a.elf
 
 fn main -> _/ebx: int {
diff --git a/linux/parse-int.mu b/linux/apps/parse-int.mu
index 8f572784..0f8c71d1 100644
--- a/linux/parse-int.mu
+++ b/linux/apps/parse-int.mu
@@ -1,7 +1,7 @@
 # parse a decimal int at the commandline
 #
 # To run:
-#   $ ./translate parse-int.mu
+#   $ ./translate apps/parse-int.mu
 #   $ ./a.elf 123
 #   $ echo $?
 #   123
diff --git a/linux/print-file.mu b/linux/apps/print-file.mu
index 6dded6ba..75ce2e39 100644
--- a/linux/print-file.mu
+++ b/linux/apps/print-file.mu
@@ -2,7 +2,7 @@
 # only ascii right now, just like the rest of Mu
 #
 # To run:
-#   $ ./translate print-file.mu
+#   $ ./translate apps/print-file.mu
 #   $ echo abc > x
 #   $ ./a.elf x
 #   abc
diff --git a/linux/raytracing/1.cc b/linux/apps/raytracing/1.cc
index 254f531c..254f531c 100644
--- a/linux/raytracing/1.cc
+++ b/linux/apps/raytracing/1.cc
diff --git a/linux/raytracing/1.cc.0 b/linux/apps/raytracing/1.cc.0
index 13d5a1b6..13d5a1b6 100644
--- a/linux/raytracing/1.cc.0
+++ b/linux/apps/raytracing/1.cc.0
diff --git a/linux/raytracing/1.mu b/linux/apps/raytracing/1.mu
index 8c92710f..dfb4ec13 100644
--- a/linux/raytracing/1.mu
+++ b/linux/apps/raytracing/1.mu
@@ -3,8 +3,8 @@
 #
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
-#   $ cd mu
-#   $ ./translate raytracing/1.mu
+#   $ cd mu/linux
+#   $ ./translate apps/raytracing/1.mu
 #   $ ./a.elf > 1.ppm
 
 fn main -> _/ebx: int {
diff --git a/linux/raytracing/1.ppm b/linux/apps/raytracing/1.ppm
index 902cc97f..902cc97f 100644
--- a/linux/raytracing/1.ppm
+++ b/linux/apps/raytracing/1.ppm
diff --git a/linux/raytracing/2.mu b/linux/apps/raytracing/2.mu
index 7de89518..92e457d3 100644
--- a/linux/raytracing/2.mu
+++ b/linux/apps/raytracing/2.mu
@@ -2,8 +2,8 @@
 #
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
-#   $ cd mu
-#   $ ./translate raytracing/2.mu
+#   $ cd mu/linux
+#   $ ./translate apps/raytracing/2.mu
 #   $ ./a.elf > 2.ppm
 
 fn main -> _/ebx: int {
diff --git a/linux/raytracing/2.ppm b/linux/apps/raytracing/2.ppm
index 902cc97f..902cc97f 100644
--- a/linux/raytracing/2.ppm
+++ b/linux/apps/raytracing/2.ppm
diff --git a/linux/raytracing/3.expected.ppm b/linux/apps/raytracing/3.expected.ppm
index 6d5b91ca..6d5b91ca 100644
--- a/linux/raytracing/3.expected.ppm
+++ b/linux/apps/raytracing/3.expected.ppm
diff --git a/linux/raytracing/3.mu b/linux/apps/raytracing/3.mu
index c64ea035..beb37136 100644
--- a/linux/raytracing/3.mu
+++ b/linux/apps/raytracing/3.mu
@@ -2,8 +2,8 @@
 #
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
-#   $ cd mu
-#   $ ./translate raytracing/3.mu
+#   $ cd mu/linux
+#   $ ./translate apps/raytracing/3.mu
 #   $ ./a.elf > 3.ppm
 
 fn ray-color _in: (addr ray), _out: (addr rgb) {
diff --git a/linux/raytracing/3.ppm b/linux/apps/raytracing/3.ppm
index 6d5b91ca..6d5b91ca 100644
--- a/linux/raytracing/3.ppm
+++ b/linux/apps/raytracing/3.ppm
diff --git a/linux/raytracing/README.md b/linux/apps/raytracing/README.md
index cc31c1af..cc31c1af 100644
--- a/linux/raytracing/README.md
+++ b/linux/apps/raytracing/README.md
diff --git a/linux/raytracing/color.h b/linux/apps/raytracing/color.h
index a8a34b26..a8a34b26 100644
--- a/linux/raytracing/color.h
+++ b/linux/apps/raytracing/color.h
diff --git a/linux/raytracing/color.mu b/linux/apps/raytracing/color.mu
index 86b3d0b6..86b3d0b6 100644
--- a/linux/raytracing/color.mu
+++ b/linux/apps/raytracing/color.mu
diff --git a/linux/raytracing/main.cc b/linux/apps/raytracing/main.cc
index 35177279..35177279 100644
--- a/linux/raytracing/main.cc
+++ b/linux/apps/raytracing/main.cc
diff --git a/linux/raytracing/ray.h b/linux/apps/raytracing/ray.h
index ed65168a..ed65168a 100644
--- a/linux/raytracing/ray.h
+++ b/linux/apps/raytracing/ray.h
diff --git a/linux/raytracing/ray.mu b/linux/apps/raytracing/ray.mu
index 20cc42e9..20cc42e9 100644
--- a/linux/raytracing/ray.mu
+++ b/linux/apps/raytracing/ray.mu
diff --git a/linux/raytracing/vec.mu b/linux/apps/raytracing/vec.mu
index 7caf7e88..7caf7e88 100644
--- a/linux/raytracing/vec.mu
+++ b/linux/apps/raytracing/vec.mu
diff --git a/linux/raytracing/vec3.h b/linux/apps/raytracing/vec3.h
index d8341d36..d8341d36 100644
--- a/linux/raytracing/vec3.h
+++ b/linux/apps/raytracing/vec3.h
diff --git a/linux/raytracing/vimrc.vim b/linux/apps/raytracing/vimrc.vim
index 348fe364..348fe364 100644
--- a/linux/raytracing/vimrc.vim
+++ b/linux/apps/raytracing/vimrc.vim
diff --git a/linux/rpn.mu b/linux/apps/rpn.mu
index f849e05d..28132470 100644
--- a/linux/rpn.mu
+++ b/linux/apps/rpn.mu
@@ -4,7 +4,7 @@
 #   No division yet.
 #
 # To build:
-#   $ ./translate rpn.mu
+#   $ ./translate apps/rpn.mu
 #
 # Example session:
 #   $ ./a.elf
diff --git a/linux/texture.mu b/linux/apps/texture.mu
index 8178424b..038a9790 100644
--- a/linux/texture.mu
+++ b/linux/apps/texture.mu
@@ -3,7 +3,7 @@
 # To run (on Linux):
 #   $ git clone https://github.com/akkartik/mu
 #   $ cd mu
-#   $ ./translate texture.mu
+#   $ ./translate apps/texture.mu
 #   $ ./a.elf > a.ppm
 
 fn main -> _/ebx: int {
diff --git a/linux/tui.mu b/linux/apps/tui.mu
index b34c3e0a..4e58b986 100644
--- a/linux/tui.mu
+++ b/linux/apps/tui.mu
@@ -1,7 +1,7 @@
 # Test some primitives for text-mode.
 #
 # To run:
-#   $ ./translate tui.mu
+#   $ ./translate apps/tui.mu
 #   $ ./a.elf
 
 fn main -> _/ebx: int {
diff --git a/linux/bootstrap/build b/linux/bootstrap/build
index de5b432d..ee4b5546 100755
--- a/linux/bootstrap/build
+++ b/linux/bootstrap/build
@@ -99,7 +99,7 @@ grep -h "^\s*void test_" bootstrap.cc  |sed 's/^\s*void \(.*\)() {.*/"\1",/'  |u
 
 older_than bootstrap_bin bootstrap.cc *_list && {
   $CXX $CXXFLAGS bootstrap.cc -o bootstrap_bin
-  echo
+  echo >&2
 }
 
 exit 0
diff --git a/linux/ex1.subx b/linux/ex1.subx
deleted file mode 100644
index 183c014a..00000000
--- a/linux/ex1.subx
+++ /dev/null
@@ -1,18 +0,0 @@
-# First program: same as https://www.muppetlabs.com/~breadbox/software/tiny/teensy.html
-# Just return 42.
-#
-# To run:
-#   $ bootstrap/bootstrap translate ex1.subx -o ex1
-#   $ bootstrap/bootstrap run ex1
-# Expected result:
-#   $ echo $?
-#   42
-
-== code
-
-Entry:
-# exit(42)
-bb/copy-to-ebx  0x2a/imm32  # 42 in hex
-e8/call  syscall_exit/disp32
-
-# . . vim:nowrap:textwidth=0