.

65 files changed, 75 insertions, 71 deletions

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