diff --git a/.github/citools/awk/awk-bats b/.github/citools/awk/awk-bats
index 58894017..9a7fc970 100755
--- a/.github/citools/awk/awk-bats
+++ b/.github/citools/awk/awk-bats
@@ -2,6 +2,8 @@
 
 declare -i retval=0
 
+export BATS_RUN_SKIPPED=true
+
 for tf in ./*.bats; do
 	echo Running: bats "${tf}"
 	time bats "${tf}" || ((retval++))
diff --git a/README.md b/README.md
index 3f1408b3..ba0412ac 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Exercism Workspace
 |   June        |  Summer-of-Sexps   |  Common-Lisp  (5/5)  |
 |   July        |  Jurassic          |  C            (5/5),  C++   (5/5),  Fortran  (0/5)  |
 |   August      |  Apps              |  Dart         (5/5),  Java  (0/5),  Kotlin   (0/5)  |
-|   September   |  Slimline          |  Awk          (2/5),  Bash\*  (5/5),  jq       (0/5),  Perl  (0/5)  |
+|   September   |  Slimline          |  Awk          (3/5),  Bash\*  (5/5),  jq       (0/5),  Perl  (0/5)  |
 |   October     |  Object-Oriented   |  |
 |   November    |  Nibbly            |  |
 |   December    |  Diversions        |  |
diff --git a/awk/README.md b/awk/README.md
index f6cf53a9..dcc315d9 100644
--- a/awk/README.md
+++ b/awk/README.md
@@ -19,3 +19,4 @@
 - [reverse-string](./reverse-string/README.md)
 - [gigasecond](./gigasecond/README.md)
 - [darts](./darts/README.md)
+- [luhn](./luhn/README.md)
diff --git a/awk/darts/run-tests-awk.txt b/awk/darts/run-tests-awk.txt
index 4b32616a..5b410bfc 100644
--- a/awk/darts/run-tests-awk.txt
+++ b/awk/darts/run-tests-awk.txt
@@ -14,9 +14,9 @@ gawk: warning: function `assertEquals' defined but never called directly
 gawk: warning: function `assert' defined but never called directly
 gawk: ./awkunit.awk:26: warning: reference to uninitialized variable `_assert_exit'
 
-real	0m0.003s
-user	0m0.003s
-sys	0m0.000s
+real	0m0.006s
+user	0m0.002s
+sys	0m0.004s
 
 gawk --lint --file=./darts.awk < /dev/null > /dev/null
 
@@ -27,8 +27,8 @@ sys	0m0.001s
 gawk --lint --file=./test-cases.awk < /dev/null > /dev/null
 
 real	0m0.004s
-user	0m0.001s
-sys	0m0.003s
+user	0m0.003s
+sys	0m0.001s
 
 exit 0
 
@@ -37,22 +37,22 @@ exit 0
 Running: bats ./test-darts.bats
 1..13
 ok 1 Missed target
-ok 2 On the outer circle # skip
-ok 3 On the middle circle # skip
-ok 4 On the inner circle # skip
-ok 5 Exactly on centre # skip
-ok 6 Near the centre # skip
-ok 7 Just within the inner circle # skip
-ok 8 Just outside the inner circle # skip
-ok 9 Just within the middle circle # skip
-ok 10 Just outside the middle circle # skip
-ok 11 Just within the outer circle # skip
-ok 12 Just outside the outer circle # skip
-ok 13 Asymmetric position between the inner and middle circles # skip
-
-real	0m0.448s
-user	0m0.270s
-sys	0m0.202s
+ok 2 On the outer circle
+ok 3 On the middle circle
+ok 4 On the inner circle
+ok 5 Exactly on centre
+ok 6 Near the centre
+ok 7 Just within the inner circle
+ok 8 Just outside the inner circle
+ok 9 Just within the middle circle
+ok 10 Just outside the middle circle
+ok 11 Just within the outer circle
+ok 12 Just outside the outer circle
+ok 13 Asymmetric position between the inner and middle circles
+
+real	0m0.546s
+user	0m0.361s
+sys	0m0.213s
 
 exit 0
 
@@ -162,9 +162,9 @@ Test 18:
 
 18 out of 18 tests passed!
 
-real	0m0.008s
-user	0m0.002s
-sys	0m0.006s
+real	0m0.007s
+user	0m0.005s
+sys	0m0.003s
 
 Tests Passed!
 
@@ -174,9 +174,9 @@ exit 0
 
 Running: misspell .
 
-real	0m0.039s
-user	0m0.045s
-sys	0m0.014s
+real	0m0.028s
+user	0m0.026s
+sys	0m0.017s
 
 ===============================================================================
 
diff --git a/awk/gigasecond/run-tests-awk.txt b/awk/gigasecond/run-tests-awk.txt
index 07e4a84a..939f9f87 100644
--- a/awk/gigasecond/run-tests-awk.txt
+++ b/awk/gigasecond/run-tests-awk.txt
@@ -14,23 +14,23 @@ gawk: warning: function `assertEquals' defined but never called directly
 gawk: warning: function `assert' defined but never called directly
 gawk: ./awkunit.awk:26: warning: reference to uninitialized variable `_assert_exit'
 
-real	0m0.003s
-user	0m0.002s
-sys	0m0.001s
+real	0m0.004s
+user	0m0.000s
+sys	0m0.003s
 
 gawk --lint --file=./gigasecond.awk < /dev/null > /dev/null
 gawk: ./gigasecond.awk:21: warning: `mktime' is a gawk extension
 gawk: ./gigasecond.awk:25: warning: `strftime' is a gawk extension
 
-real	0m0.004s
+real	0m0.005s
 user	0m0.001s
 sys	0m0.003s
 
 gawk --lint --file=./test-cases.awk < /dev/null > /dev/null
 
 real	0m0.003s
-user	0m0.003s
-sys	0m0.000s
+user	0m0.001s
+sys	0m0.002s
 
 exit 0
 
@@ -39,14 +39,14 @@ exit 0
 Running: bats ./test-gigasecond.bats
 1..5
 ok 1 date only specificaion of time
-ok 2 second test for date only specification of time # skip
-ok 3 third test for date only specification of time # skip
-ok 4 full time specified # skip
-ok 5 full time with day roll-over # skip
+ok 2 second test for date only specification of time
+ok 3 third test for date only specification of time
+ok 4 full time specified
+ok 5 full time with day roll-over
 
-real	0m0.226s
-user	0m0.136s
-sys	0m0.108s
+real	0m0.216s
+user	0m0.145s
+sys	0m0.086s
 
 exit 0
 
@@ -101,9 +101,9 @@ Test 7:
 
 7 out of 7 tests passed!
 
-real	0m0.003s
+real	0m0.008s
 user	0m0.002s
-sys	0m0.002s
+sys	0m0.006s
 
 Tests Passed!
 
@@ -113,9 +113,9 @@ exit 0
 
 Running: misspell .
 
-real	0m0.025s
-user	0m0.030s
-sys	0m0.010s
+real	0m0.036s
+user	0m0.042s
+sys	0m0.013s
 
 ===============================================================================
 
diff --git a/awk/hello-world/run-tests-awk.txt b/awk/hello-world/run-tests-awk.txt
index ab335c5b..43e328f3 100644
--- a/awk/hello-world/run-tests-awk.txt
+++ b/awk/hello-world/run-tests-awk.txt
@@ -14,22 +14,22 @@ gawk: warning: function `assertEquals' defined but never called directly
 gawk: warning: function `assert' defined but never called directly
 gawk: ./awkunit.awk:26: warning: reference to uninitialized variable `_assert_exit'
 
-real	0m0.002s
-user	0m0.001s
-sys	0m0.001s
+real	0m0.003s
+user	0m0.002s
+sys	0m0.000s
 
 gawk --lint --file=./hello-world.awk < /dev/null > /dev/null
 
 real	0m0.002s
-user	0m0.001s
-sys	0m0.001s
+user	0m0.002s
+sys	0m0.000s
 
 gawk --lint --file=./test-cases.awk < /dev/null > /dev/null
 gawk: ./test-cases.awk:10: warning: subscript of array `cases' is null string
 
 real	0m0.002s
-user	0m0.000s
-sys	0m0.002s
+user	0m0.001s
+sys	0m0.001s
 
 exit 0
 
@@ -39,9 +39,9 @@ Running: bats ./test-hello-world.bats
 1..1
 ok 1 Say Hi!
 
-real	0m0.084s
-user	0m0.050s
-sys	0m0.049s
+real	0m0.112s
+user	0m0.071s
+sys	0m0.059s
 
 exit 0
 
@@ -67,8 +67,8 @@ Test 1:
 1 out of 2 tests passed!
 
 real	0m0.005s
-user	0m0.002s
-sys	0m0.003s
+user	0m0.003s
+sys	0m0.002s
 
 Tests Passed!
 
@@ -78,9 +78,9 @@ exit 0
 
 Running: misspell .
 
-real	0m0.035s
-user	0m0.036s
-sys	0m0.013s
+real	0m0.025s
+user	0m0.027s
+sys	0m0.011s
 
 ===============================================================================
 
diff --git a/awk/luhn/.exercism/config.json b/awk/luhn/.exercism/config.json
new file mode 100644
index 00000000..10a7788c
--- /dev/null
+++ b/awk/luhn/.exercism/config.json
@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "luhn.awk"
+    ],
+    "test": [
+      "test-luhn.bats"
+    ],
+    "example": [
+      ".meta/example.awk"
+    ]
+  },
+  "blurb": "Given a number determine whether or not it is valid per the Luhn formula.",
+  "source": "The Luhn Algorithm on Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Luhn_algorithm"
+}
diff --git a/awk/luhn/.exercism/metadata.json b/awk/luhn/.exercism/metadata.json
new file mode 100644
index 00000000..9291a5b9
--- /dev/null
+++ b/awk/luhn/.exercism/metadata.json
@@ -0,0 +1 @@
+{"track":"awk","exercise":"luhn","id":"09b7d064ae9e4eb6a98b19e7e5d7d222","url":"https://exercism.org/tracks/awk/exercises/luhn","handle":"vpayno","is_requester":true,"auto_approve":false}
\ No newline at end of file
diff --git a/awk/luhn/HELP.md b/awk/luhn/HELP.md
new file mode 100644
index 00000000..a672b11e
--- /dev/null
+++ b/awk/luhn/HELP.md
@@ -0,0 +1,99 @@
+# Help
+
+## Running the tests
+
+Each exercise contains a test file.
+Run the tests using the `bats` program.
+```bash
+bats test-hello-world.bats
+```
+
+`bats` will need to be installed.
+See the [Testing on the Bash track][bash] page for instructions to install `bats` for your system.
+
+### bats is implemented in bash
+
+The bats file is a bash script, with some special functions recognized by the `bats` command.
+You'll see some tests that look like
+```sh
+gawk -f some-exercise.awk <<< "some,input,here"
+```
+That `<<<` syntax is a bash [Here String][here-string].
+It sends the string on the right-hand side into the standard input of the program on the left-hand side.
+It is ([approximately][so]) the same as
+```sh
+echo "some,input,here" | gawk -f some-exercise.awk
+```
+
+## Help for assert functions
+
+The tests use functions from the [bats-assert][bats-assert] library.
+Help for the various `assert*` functions can be found there.
+
+## Skipped tests
+
+Solving an exercise means making all its tests pass.
+By default, only one test (the first one) is executed when you run the tests.
+This is intentional, as it allows you to focus on just making that one test pass.
+Once it passes, you can enable the next test by commenting out or removing the
+
+    [[ $BATS_RUN_SKIPPED == true ]] || skip
+
+annotations prepending other tests.
+
+## Overriding skips
+
+To run all tests, including the ones with `skip` annotations, you can run:
+```bash
+BATS_RUN_SKIPPED=true bats test-some-exercise.bats
+```
+
+It can be convenient to use a wrapper function to save on typing: in `bash` you can do:
+```bash
+bats() {
+    BATS_RUN_SKIPPED=true command bats *.bats
+}
+```
+Then run tests with just:
+```bash
+bats
+```
+
+[bash]: https://exercism.org/docs/tracks/bash/tests
+[bats-assert]: https://github.com/bats-core/bats-assert
+[here-string]: https://www.gnu.org/software/bash/manual/bash.html#Here-Strings
+[so]: https://unix.stackexchange.com/a/80372/4667
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit luhn.awk` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [AWK track's documentation](https://exercism.org/docs/tracks/awk)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+Places to look for help for AWK questions:
+
+* [Stack Overflow `awk` tag][so].
+* check the Resources section of the [Stack Overflow `awk` tag into page][so-info].
+* raise an issue at the [exercism/awk][github] Github repository.
+* IRC: `irc://irc.liberachat.net/#awk`, `irc://irc.liberachat.net/#exercism`
+    * see [Libera.chat][libera] if you're unfamiliar with IRC.
+
+
+[so]: https://stackoverflow.com/tags/awk
+[so-info]: https://stackoverflow.com/tags/awk/info
+[github]: https://github.com/exercism/awk
+[libera]: https://libera.chat
\ No newline at end of file
diff --git a/awk/luhn/README.md b/awk/luhn/README.md
new file mode 100644
index 00000000..7f26fff7
--- /dev/null
+++ b/awk/luhn/README.md
@@ -0,0 +1,86 @@
+# Luhn
+
+Welcome to Luhn on Exercism's AWK Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Given a number determine whether or not it is valid per the Luhn formula.
+
+The [Luhn algorithm][luhn] is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers and Canadian Social Insurance Numbers.
+
+The task is to check if a given string is valid.
+
+## Validating a Number
+
+Strings of length 1 or less are not valid.
+Spaces are allowed in the input, but they should be stripped before checking.
+All other non-digit characters are disallowed.
+
+### Example 1: valid credit card number
+
+```text
+4539 3195 0343 6467
+```
+
+The first step of the Luhn algorithm is to double every second digit, starting from the right.
+We will be doubling
+
+```text
+4_3_ 3_9_ 0_4_ 6_6_
+```
+
+If doubling the number results in a number greater than 9 then subtract 9 from the product.
+The results of our doubling:
+
+```text
+8569 6195 0383 3437
+```
+
+Then sum all of the digits:
+
+```text
+8+5+6+9+6+1+9+5+0+3+8+3+3+4+3+7 = 80
+```
+
+If the sum is evenly divisible by 10, then the number is valid.
+This number is valid!
+
+### Example 2: invalid credit card number
+
+```text
+8273 1232 7352 0569
+```
+
+Double the second digits, starting from the right
+
+```text
+7253 2262 5312 0539
+```
+
+Sum the digits
+
+```text
+7+2+5+3+2+2+6+2+5+3+1+2+0+5+3+9 = 57
+```
+
+57 is not evenly divisible by 10, so this number is not valid.
+
+[luhn]: https://en.wikipedia.org/wiki/Luhn_algorithm
+
+## Source
+
+### Created by
+
+- @glennj
+
+### Based on
+
+The Luhn Algorithm on Wikipedia - https://en.wikipedia.org/wiki/Luhn_algorithm
+
+### My Solution
+
+- [my solution](./luhn.awk)
+- [awkunit tests](./luhn_test.awk)
+- [test cases](./test-cases.awk)
+- [run-tests](./run-tests-awk.txt)
diff --git a/awk/luhn/awkunit.awk b/awk/luhn/awkunit.awk
new file mode 120000
index 00000000..38a08adf
--- /dev/null
+++ b/awk/luhn/awkunit.awk
@@ -0,0 +1 @@
+../.lib/awkunit.awk
\ No newline at end of file
diff --git a/awk/luhn/bats-extra.bash b/awk/luhn/bats-extra.bash
new file mode 100644
index 00000000..54d48070
--- /dev/null
+++ b/awk/luhn/bats-extra.bash
@@ -0,0 +1,637 @@
+# This is the source code for bats-support and bats-assert, concatenated
+# * https://github.com/bats-core/bats-support
+# * https://github.com/bats-core/bats-assert
+#
+# Comments have been removed to save space. See the git repos for full source code.
+
+############################################################
+#
+# bats-support - Supporting library for Bats test helpers
+#
+# Written in 2016 by Zoltan Tombol <zoltan dot tombol at gmail dot com>
+#
+# To the extent possible under law, the author(s) have dedicated all
+# copyright and related and neighboring rights to this software to the
+# public domain worldwide. This software is distributed without any
+# warranty.
+#
+# You should have received a copy of the CC0 Public Domain Dedication
+# along with this software. If not, see
+# <http://creativecommons.org/publicdomain/zero/1.0/>.
+#
+
+fail() {
+  (( $# == 0 )) && batslib_err || batslib_err "$@"
+  return 1
+}
+
+batslib_is_caller() {
+  local -i is_mode_direct=1
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+      -i|--indirect) is_mode_direct=0; shift ;;
+      --) shift; break ;;
+      *) break ;;
+    esac
+  done
+
+  # Arguments.
+  local -r func="$1"
+
+  # Check call stack.
+  if (( is_mode_direct )); then
+    [[ $func == "${FUNCNAME[2]}" ]] && return 0
+  else
+    local -i depth
+    for (( depth=2; depth<${#FUNCNAME[@]}; ++depth )); do
+      [[ $func == "${FUNCNAME[$depth]}" ]] && return 0
+    done
+  fi
+
+  return 1
+}
+
+batslib_err() {
+  { if (( $# > 0 )); then
+      echo "$@"
+    else
+      cat -
+    fi
+  } >&2
+}
+
+batslib_count_lines() {
+  local -i n_lines=0
+  local line
+  while IFS='' read -r line || [[ -n $line ]]; do
+    (( ++n_lines ))
+  done < <(printf '%s' "$1")
+  echo "$n_lines"
+}
+
+batslib_is_single_line() {
+  for string in "$@"; do
+    (( $(batslib_count_lines "$string") > 1 )) && return 1
+  done
+  return 0
+}
+
+batslib_get_max_single_line_key_width() {
+  local -i max_len=-1
+  while (( $# != 0 )); do
+    local -i key_len="${#1}"
+    batslib_is_single_line "$2" && (( key_len > max_len )) && max_len="$key_len"
+    shift 2
+  done
+  echo "$max_len"
+}
+
+batslib_print_kv_single() {
+  local -ir col_width="$1"; shift
+  while (( $# != 0 )); do
+    printf '%-*s : %s\n' "$col_width" "$1" "$2"
+    shift 2
+  done
+}
+
+batslib_print_kv_multi() {
+  while (( $# != 0 )); do
+    printf '%s (%d lines):\n' "$1" "$( batslib_count_lines "$2" )"
+    printf '%s\n' "$2"
+    shift 2
+  done
+}
+
+batslib_print_kv_single_or_multi() {
+  local -ir width="$1"; shift
+  local -a pairs=( "$@" )
+
+  local -a values=()
+  local -i i
+  for (( i=1; i < ${#pairs[@]}; i+=2 )); do
+    values+=( "${pairs[$i]}" )
+  done
+
+  if batslib_is_single_line "${values[@]}"; then
+    batslib_print_kv_single "$width" "${pairs[@]}"
+  else
+    local -i i
+    for (( i=1; i < ${#pairs[@]}; i+=2 )); do
+      pairs[$i]="$( batslib_prefix < <(printf '%s' "${pairs[$i]}") )"
+    done
+    batslib_print_kv_multi "${pairs[@]}"
+  fi
+}
+
+batslib_prefix() {
+  local -r prefix="${1:-  }"
+  local line
+  while IFS='' read -r line || [[ -n $line ]]; do
+    printf '%s%s\n' "$prefix" "$line"
+  done
+}
+
+batslib_mark() {
+  local -r symbol="$1"; shift
+  # Sort line numbers.
+  set -- $( sort -nu <<< "$( printf '%d\n' "$@" )" )
+
+  local line
+  local -i idx=0
+  while IFS='' read -r line || [[ -n $line ]]; do
+    if (( ${1:--1} == idx )); then
+      printf '%s\n' "${symbol}${line:${#symbol}}"
+      shift
+    else
+      printf '%s\n' "$line"
+    fi
+    (( ++idx ))
+  done
+}
+
+batslib_decorate() {
+  echo
+  echo "-- $1 --"
+  cat -
+  echo '--'
+  echo
+}
+
+############################################################
+
+assert() {
+  if ! "$@"; then
+    batslib_print_kv_single 10 'expression' "$*" \
+    | batslib_decorate 'assertion failed' \
+    | fail
+  fi
+}
+
+assert_equal() {
+  if [[ $1 != "$2" ]]; then
+    batslib_print_kv_single_or_multi 8 \
+    'expected' "$2" \
+    'actual'   "$1" \
+    | batslib_decorate 'values do not equal' \
+    | fail
+  fi
+}
+
+assert_failure() {
+  : "${output?}"
+  : "${status?}"
+
+  (( $# > 0 )) && local -r expected="$1"
+  if (( status == 0 )); then
+    batslib_print_kv_single_or_multi 6 'output' "$output" \
+    | batslib_decorate 'command succeeded, but it was expected to fail' \
+    | fail
+  elif (( $# > 0 )) && (( status != expected )); then
+    { local -ir width=8
+      batslib_print_kv_single "$width" \
+      'expected' "$expected" \
+      'actual'   "$status"
+      batslib_print_kv_single_or_multi "$width" \
+      'output' "$output"
+    } \
+    | batslib_decorate 'command failed as expected, but status differs' \
+    | fail
+  fi
+}
+
+assert_line() {
+  local -i is_match_line=0
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  : "${lines?}"
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+    -n|--index)
+      if (( $# < 2 )) || ! [[ $2 =~ ^([0-9]|[1-9][0-9]+)$ ]]; then
+        echo "\`--index' requires an integer argument: \`$2'" \
+        | batslib_decorate 'ERROR: assert_line' \
+        | fail
+        return $?
+      fi
+      is_match_line=1
+      local -ri idx="$2"
+      shift 2
+      ;;
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: assert_line' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local -r expected="$1"
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $expected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$expected'" \
+    | batslib_decorate 'ERROR: assert_line' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_match_line )); then
+    # Specific line.
+    if (( is_mode_regexp )); then
+      if ! [[ ${lines[$idx]} =~ $expected ]]; then
+        batslib_print_kv_single 6 \
+        'index' "$idx" \
+        'regexp' "$expected" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'regular expression does not match line' \
+        | fail
+      fi
+    elif (( is_mode_partial )); then
+      if [[ ${lines[$idx]} != *"$expected"* ]]; then
+        batslib_print_kv_single 9 \
+        'index'     "$idx" \
+        'substring' "$expected" \
+        'line'      "${lines[$idx]}" \
+        | batslib_decorate 'line does not contain substring' \
+        | fail
+      fi
+    else
+      if [[ ${lines[$idx]} != "$expected" ]]; then
+        batslib_print_kv_single 8 \
+        'index'    "$idx" \
+        'expected' "$expected" \
+        'actual'   "${lines[$idx]}" \
+        | batslib_decorate 'line differs' \
+        | fail
+      fi
+    fi
+  else
+    # Contained in output.
+    if (( is_mode_regexp )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} =~ $expected ]] && return 0
+      done
+      { local -ar single=( 'regexp' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'no output line matches regular expression' \
+      | fail
+    elif (( is_mode_partial )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} == *"$expected"* ]] && return 0
+      done
+      { local -ar single=( 'substring' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'no output line contains substring' \
+      | fail
+    else
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} == "$expected" ]] && return 0
+      done
+      { local -ar single=( 'line' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'output does not contain line' \
+      | fail
+    fi
+  fi
+}
+
+assert_output() {
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  local -i is_mode_nonempty=0
+  local -i use_stdin=0
+  : "${output?}"
+
+  # Handle options.
+  if (( $# == 0 )); then
+    is_mode_nonempty=1
+  fi
+
+  while (( $# > 0 )); do
+    case "$1" in
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    -|--stdin) use_stdin=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: assert_output' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local expected
+  if (( use_stdin )); then
+    expected="$(cat -)"
+  else
+    expected="${1-}"
+  fi
+
+  # Matching.
+  if (( is_mode_nonempty )); then
+    if [ -z "$output" ]; then
+      echo 'expected non-empty output, but output was empty' \
+      | batslib_decorate 'no output' \
+      | fail
+    fi
+  elif (( is_mode_regexp )); then
+    if [[ '' =~ $expected ]] || (( $? == 2 )); then
+      echo "Invalid extended regular expression: \`$expected'" \
+      | batslib_decorate 'ERROR: assert_output' \
+      | fail
+    elif ! [[ $output =~ $expected ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'regexp'  "$expected" \
+      'output' "$output" \
+      | batslib_decorate 'regular expression does not match output' \
+      | fail
+    fi
+  elif (( is_mode_partial )); then
+    if [[ $output != *"$expected"* ]]; then
+      batslib_print_kv_single_or_multi 9 \
+      'substring' "$expected" \
+      'output'    "$output" \
+      | batslib_decorate 'output does not contain substring' \
+      | fail
+    fi
+  else
+    if [[ $output != "$expected" ]]; then
+      batslib_print_kv_single_or_multi 8 \
+      'expected' "$expected" \
+      'actual'   "$output" \
+      | batslib_decorate 'output differs' \
+      | fail
+    fi
+  fi
+}
+
+assert_success() {
+  : "${output?}"
+  : "${status?}"
+
+  if (( status != 0 )); then
+    { local -ir width=6
+      batslib_print_kv_single "$width" 'status' "$status"
+      batslib_print_kv_single_or_multi "$width" 'output' "$output"
+    } \
+    | batslib_decorate 'command failed' \
+    | fail
+  fi
+}
+
+refute() {
+  if "$@"; then
+    batslib_print_kv_single 10 'expression' "$*" \
+    | batslib_decorate 'assertion succeeded, but it was expected to fail' \
+    | fail
+  fi
+}
+
+refute_line() {
+  local -i is_match_line=0
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  : "${lines?}"
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+    -n|--index)
+      if (( $# < 2 )) || ! [[ $2 =~ ^([0-9]|[1-9][0-9]+)$ ]]; then
+        echo "\`--index' requires an integer argument: \`$2'" \
+        | batslib_decorate 'ERROR: refute_line' \
+        | fail
+        return $?
+      fi
+      is_match_line=1
+      local -ri idx="$2"
+      shift 2
+      ;;
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: refute_line' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local -r unexpected="$1"
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $unexpected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$unexpected'" \
+    | batslib_decorate 'ERROR: refute_line' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_match_line )); then
+    # Specific line.
+    if (( is_mode_regexp )); then
+      if [[ ${lines[$idx]} =~ $unexpected ]]; then
+        batslib_print_kv_single 6 \
+        'index' "$idx" \
+        'regexp' "$unexpected" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'regular expression should not match line' \
+        | fail
+      fi
+    elif (( is_mode_partial )); then
+      if [[ ${lines[$idx]} == *"$unexpected"* ]]; then
+        batslib_print_kv_single 9 \
+        'index'     "$idx" \
+        'substring' "$unexpected" \
+        'line'      "${lines[$idx]}" \
+        | batslib_decorate 'line should not contain substring' \
+        | fail
+      fi
+    else
+      if [[ ${lines[$idx]} == "$unexpected" ]]; then
+        batslib_print_kv_single 5 \
+        'index' "$idx" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'line should differ' \
+        | fail
+      fi
+    fi
+  else
+    # Line contained in output.
+    if (( is_mode_regexp )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} =~ $unexpected ]]; then
+          { local -ar single=( 'regexp' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'no line should match the regular expression' \
+          | fail
+          return $?
+        fi
+      done
+    elif (( is_mode_partial )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} == *"$unexpected"* ]]; then
+          { local -ar single=( 'substring' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'no line should contain substring' \
+          | fail
+          return $?
+        fi
+      done
+    else
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} == "$unexpected" ]]; then
+          { local -ar single=( 'line' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'line should not be in output' \
+          | fail
+          return $?
+        fi
+      done
+    fi
+  fi
+}
+
+refute_output() {
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  local -i is_mode_empty=0
+  local -i use_stdin=0
+  : "${output?}"
+
+  # Handle options.
+  if (( $# == 0 )); then
+    is_mode_empty=1
+  fi
+
+  while (( $# > 0 )); do
+    case "$1" in
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    -|--stdin) use_stdin=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: refute_output' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local unexpected
+  if (( use_stdin )); then
+    unexpected="$(cat -)"
+  else
+    unexpected="${1-}"
+  fi
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $unexpected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$unexpected'" \
+    | batslib_decorate 'ERROR: refute_output' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_mode_empty )); then
+    if [ -n "$output" ]; then
+      batslib_print_kv_single_or_multi 6 \
+      'output' "$output" \
+      | batslib_decorate 'output non-empty, but expected no output' \
+      | fail
+    fi
+  elif (( is_mode_regexp )); then
+    if [[ $output =~ $unexpected ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'regexp'  "$unexpected" \
+      'output' "$output" \
+      | batslib_decorate 'regular expression should not match output' \
+      | fail
+    fi
+  elif (( is_mode_partial )); then
+    if [[ $output == *"$unexpected"* ]]; then
+      batslib_print_kv_single_or_multi 9 \
+      'substring' "$unexpected" \
+      'output'    "$output" \
+      | batslib_decorate 'output should not contain substring' \
+      | fail
+    fi
+  else
+    if [[ $output == "$unexpected" ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'output' "$output" \
+      | batslib_decorate 'output equals, but it was expected to differ' \
+      | fail
+    fi
+  fi
+}
diff --git a/awk/luhn/luhn.awk b/awk/luhn/luhn.awk
new file mode 100644
index 00000000..718f2f76
--- /dev/null
+++ b/awk/luhn/luhn.awk
@@ -0,0 +1,74 @@
+#!/usr/bin/gawk --lint --file
+
+function reverse_string(forward) {
+    reversed = ""
+
+    split(forward, chars, "")
+
+    for (i = 1; i <= length(chars); i++) {
+        reversed = chars[i] reversed
+    }
+
+    return reversed
+}
+
+function is_valid(input) {
+    if (length(input) <= 1) {
+        return "false"
+    }
+
+    if (match(input, /^[ 0-9]+$/)) {
+        return "true"
+    }
+
+    return "false"
+}
+
+function luhn(input) {
+    if(is_valid(input) == "false") {
+        return "false"
+    }
+
+    _ = gsub(/ /, "", input)
+
+    if (input == 0 && length(input) == 1) {
+        return "false"
+    }
+
+    _ = split(reverse_string(input), numbers, "")
+
+    sum = 0
+    for (i = 1; i <= length(input); i++) {
+        digit = numbers[i]
+
+        if(i % 2 != 0) {
+            sum += digit
+            continue
+        }
+
+        new_digit = digit * 2
+
+        if(new_digit > 9) {
+            new_digit -= 9
+        }
+
+        numbers[i] = new_digit
+        sum += new_digit
+    }
+
+    if (sum % 10 == 0) {
+        return "true"
+    }
+
+    return "false"
+}
+
+BEGIN {
+}
+
+{
+    print luhn($0)
+}
+
+END {
+}
diff --git a/awk/luhn/luhn_test.awk b/awk/luhn/luhn_test.awk
new file mode 100644
index 00000000..721898fb
--- /dev/null
+++ b/awk/luhn/luhn_test.awk
@@ -0,0 +1,125 @@
+#!/usr/bin/gawk --lint --file
+
+@include "awkunit"
+@include "test-cases"
+@include "luhn"
+
+passed = 0
+testCount = 0
+
+function _debugTestPre() {
+    printf "Test %s:\n", (passed + 1)
+    printf "     input -> [%s]\n", input
+}
+
+function _debugTestPost() {
+    passed = passed + 1
+    printf "    output -> [%s]\n", got
+    printf "    result -> passed\n\n"
+}
+
+function test_reverse_string() {
+    input = "0123456789"
+    want = "9876543210"
+
+    _debugTestPre()
+    got = reverse_string(input)
+
+    assertEquals(got, want)
+    _debugTestPost()
+}
+
+function test_is_valid_empty() {
+    input = ""
+    want = "false"
+
+    _debugTestPre()
+    got = is_valid(input)
+
+    assertEquals(got, want)
+    _debugTestPost()
+}
+
+function test_is_valid_valid() {
+    input = "123 456"
+    want = "true"
+
+    _debugTestPre()
+    got = is_valid(input)
+
+    assertEquals(got, want)
+    _debugTestPost()
+}
+
+function test_is_valid_not_valid() {
+    input = "abc 456"
+    want = "false"
+
+    _debugTestPre()
+    got = is_valid(input)
+
+    assertEquals(got, want)
+    _debugTestPost()
+}
+
+function testLuhn_empty() {
+    input = ""
+    want = "false"
+
+    # _ = split(input, a, " ")
+
+    _debugTestPre()
+    got = luhn(input)
+
+    assertEquals(got, want)
+    _debugTestPost()
+}
+
+function casesLuhn() {
+    printf "Running %d test cases\n\n", length(cases)
+    caseNum = 0
+
+    # Associative arrays don't preserve insert order.
+    for (key in cases) {
+        input = key
+        want = cases[key]
+
+        # _ = split(input, a, " ")
+
+        _debugTestPre()
+        got = luhn(input)
+
+        assertEquals(got, want)
+        _debugTestPost()
+    }
+}
+
+BEGIN {
+    exit 0
+}
+
+END {
+    cmd = "grep --no-filename --count ^function\\ test *_test.awk"
+    cmd | getline testCount
+
+    printf "\nRunning %d tests...\n\n", testCount
+
+    testCount = testCount + length(cases)
+
+    test_reverse_string()
+
+    test_is_valid_empty()
+    test_is_valid_valid()
+    test_is_valid_not_valid()
+
+    # running tests with a lot of duplication
+    testLuhn_empty()
+
+    # running tests with reduced duplication
+    casesLuhn()
+
+    print "\n" passed " out of " testCount " tests passed!"
+
+    # add exit here to keep it from looping
+    exit 0
+}
diff --git a/awk/luhn/run-tests-awk.txt b/awk/luhn/run-tests-awk.txt
new file mode 100644
index 00000000..2edeaf0a
--- /dev/null
+++ b/awk/luhn/run-tests-awk.txt
@@ -0,0 +1,236 @@
+Running automated test file(s):
+
+
+===============================================================================
+
+AWKLIBPATH=../.lib
+
+awkunit.awk
+awkunit.so
+
+gawk --lint --file=./awkunit.awk < /dev/null > /dev/null
+gawk: ./awkunit.awk:3: warning: `load' is a gawk extension
+gawk: warning: function `assertEquals' defined but never called directly
+gawk: warning: function `assert' defined but never called directly
+gawk: ./awkunit.awk:26: warning: reference to uninitialized variable `_assert_exit'
+
+real	0m0.003s
+user	0m0.000s
+sys	0m0.003s
+
+gawk --lint --file=./luhn.awk < /dev/null > /dev/null
+
+real	0m0.004s
+user	0m0.002s
+sys	0m0.002s
+
+gawk --lint --file=./test-cases.awk < /dev/null > /dev/null
+
+real	0m0.003s
+user	0m0.002s
+sys	0m0.001s
+
+exit 0
+
+===============================================================================
+
+Running: bats ./test-luhn.bats
+1..22
+ok 1 single digit strings can not be valid
+ok 2 a single zero is invalid
+ok 3 a simple valid SIN that remains valid if reversed
+ok 4 a simple valid SIN that becomes invalid if reversed
+ok 5 a valid Canadian SIN
+ok 6 invalid Canadian SIN
+ok 7 invalid credit card
+ok 8 invalid long number with an even remainder
+ok 9 invalid long number with a remainder divisible by 5
+ok 10 valid number with an even number of digits
+ok 11 valid number with an odd number of spaces
+ok 12 valid strings with a non-digit included become invalid
+ok 13 valid strings with punctuation included become invalid
+ok 14 valid strings with symbols included become invalid
+ok 15 single zero with space is invalid
+ok 16 more than a single zero is valid
+ok 17 input digit 9 is correctly converted to output digit 9
+ok 18 very long input is valid
+ok 19 valid luhn with an odd number of digits and non zero first digit
+ok 20 using ascii value for non-doubled non-digit isn't allowed
+ok 21 using ascii value for doubled non-digit isn't allowed
+ok 22 non-numeric, non-space char in the middle with a sum that's divisible by 10 isn't allowed
+
+real	0m0.808s
+user	0m0.540s
+sys	0m0.297s
+
+exit 0
+
+===============================================================================
+
+AWKLIBPATH=../.lib
+
+awkunit.awk
+awkunit.so
+
+Running: gawk --file ./luhn_test.awk && printf \n%s\n Tests Passed! || printf \n%s\n Tests Failed!
+
+Running 5 tests...
+
+Test 1:
+     input -> [0123456789]
+    output -> [9876543210]
+    result -> passed
+
+Test 2:
+     input -> []
+    output -> [false]
+    result -> passed
+
+Test 3:
+     input -> [123 456]
+    output -> [true]
+    result -> passed
+
+Test 4:
+     input -> [abc 456]
+    output -> [false]
+    result -> passed
+
+Test 5:
+     input -> []
+    output -> [false]
+    result -> passed
+
+Running 22 test cases
+
+Test 6:
+     input -> [1 2345 6789 1234 5678 9012]
+    output -> [false]
+    result -> passed
+
+Test 7:
+     input -> [1 2345 6789 1234 5678 9013]
+    output -> [false]
+    result -> passed
+
+Test 8:
+     input -> [ 0]
+    output -> [false]
+    result -> passed
+
+Test 9:
+     input -> [59%59]
+    output -> [false]
+    result -> passed
+
+Test 10:
+     input -> [055 444 285]
+    output -> [true]
+    result -> passed
+
+Test 11:
+     input -> [055£ 444$ 285]
+    output -> [false]
+    result -> passed
+
+Test 12:
+     input -> [0000 0]
+    output -> [true]
+    result -> passed
+
+Test 13:
+     input -> [095 245 88]
+    output -> [true]
+    result -> passed
+
+Test 14:
+     input -> [055 444 286]
+    output -> [false]
+    result -> passed
+
+Test 15:
+     input -> [091]
+    output -> [true]
+    result -> passed
+
+Test 16:
+     input -> [234 567 891 234]
+    output -> [true]
+    result -> passed
+
+Test 17:
+     input -> [055-444-285]
+    output -> [false]
+    result -> passed
+
+Test 18:
+     input -> [:9]
+    output -> [false]
+    result -> passed
+
+Test 19:
+     input -> [055b 444 285]
+    output -> [false]
+    result -> passed
+
+Test 20:
+     input -> [8273 1232 7352 0569]
+    output -> [false]
+    result -> passed
+
+Test 21:
+     input -> [9999999999 9999999999 9999999999 9999999999]
+    output -> [true]
+    result -> passed
+
+Test 22:
+     input -> [059]
+    output -> [true]
+    result -> passed
+
+Test 23:
+     input -> [055a 444 285]
+    output -> [false]
+    result -> passed
+
+Test 24:
+     input -> [0]
+    output -> [false]
+    result -> passed
+
+Test 25:
+     input -> [1]
+    output -> [false]
+    result -> passed
+
+Test 26:
+     input -> [59]
+    output -> [true]
+    result -> passed
+
+Test 27:
+     input -> [109]
+    output -> [true]
+    result -> passed
+
+
+27 out of 27 tests passed!
+
+real	0m0.006s
+user	0m0.003s
+sys	0m0.004s
+
+Tests Passed!
+
+exit 0
+
+===============================================================================
+
+Running: misspell .
+
+real	0m0.028s
+user	0m0.032s
+sys	0m0.013s
+
+===============================================================================
+
diff --git a/awk/luhn/test-cases.awk b/awk/luhn/test-cases.awk
new file mode 100644
index 00000000..a7f615e2
--- /dev/null
+++ b/awk/luhn/test-cases.awk
@@ -0,0 +1,34 @@
+#!/usr/bin/gawk --lint --file
+# test-cases.awk
+
+#   key: input
+# value: output
+
+BEGIN {
+    cases["1"]="false"
+    cases["0"]="false"
+    cases["055 444 286"]="false"
+    cases["8273 1232 7352 0569"]="false"
+    cases["1 2345 6789 1234 5678 9012"]="false"
+    cases["1 2345 6789 1234 5678 9013"]="false"
+    cases["055a 444 285"]="false"
+    cases["055-444-285"]="false"
+    cases["055£ 444$ 285"]="false"
+    cases[" 0"]="false"
+    cases["055b 444 285"]="false"
+    cases[":9"]="false"
+    cases["59%59"]="false"
+
+    cases["059"]="true"
+    cases["59"]="true"
+    cases["055 444 285"]="true"
+    cases["095 245 88"]="true"
+    cases["234 567 891 234"]="true"
+    cases["0000 0"]="true"
+    cases["091"]="true"
+    cases["9999999999 9999999999 9999999999 9999999999"]="true"
+    cases["109"]="true"
+
+    # add exit here to keep it from waiting for input
+    exit 0
+}
diff --git a/awk/luhn/test-luhn.bats b/awk/luhn/test-luhn.bats
new file mode 100644
index 00000000..ff360686
--- /dev/null
+++ b/awk/luhn/test-luhn.bats
@@ -0,0 +1,156 @@
+#!/usr/bin/env bats
+load bats-extra
+
+@test "single digit strings can not be valid" {
+  #[[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "1"
+  assert_success
+  assert_output "false"
+}
+
+@test "a single zero is invalid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "0"
+  assert_success
+  assert_output "false"
+}
+
+@test "a simple valid SIN that remains valid if reversed" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "059"
+  assert_success
+  assert_output "true"
+}
+
+@test "a simple valid SIN that becomes invalid if reversed" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "59"
+  assert_success
+  assert_output "true"
+}
+
+@test "a valid Canadian SIN" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "055 444 285"
+  assert_success
+  assert_output "true"
+}
+
+@test "invalid Canadian SIN" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "055 444 286"
+  assert_success
+  assert_output "false"
+}
+
+@test "invalid credit card" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "8273 1232 7352 0569"
+  assert_success
+  assert_output "false"
+}
+
+@test  "invalid long number with an even remainder" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "1 2345 6789 1234 5678 9012"
+  assert_success
+  assert_output "false"
+}
+
+@test  "invalid long number with a remainder divisible by 5" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "1 2345 6789 1234 5678 9013"
+  assert_success
+  assert_output "false"
+}
+
+@test "valid number with an even number of digits" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "095 245 88"
+  assert_success
+  assert_output "true"
+}
+
+@test "valid number with an odd number of spaces" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "234 567 891 234"
+  assert_success
+  assert_output "true"
+}
+
+@test "valid strings with a non-digit included become invalid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "055a 444 285"
+  assert_success
+  assert_output "false"
+}
+
+@test "valid strings with punctuation included become invalid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "055-444-285"
+  assert_success
+  assert_output "false"
+}
+
+@test "valid strings with symbols included become invalid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "055£ 444$ 285"
+  assert_success
+  assert_output "false"
+}
+
+@test "single zero with space is invalid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< " 0"
+  assert_success
+  assert_output "false"
+}
+
+@test "more than a single zero is valid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "0000 0"
+  assert_success
+  assert_output "true"
+}
+
+@test "input digit 9 is correctly converted to output digit 9" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "091"
+  assert_success
+  assert_output "true"
+}
+
+@test "very long input is valid" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "9999999999 9999999999 9999999999 9999999999"
+  assert_success
+  assert_output "true"
+}
+
+@test "valid luhn with an odd number of digits and non zero first digit" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "109"
+  assert_success
+  assert_output "true"
+}
+
+@test "using ascii value for non-doubled non-digit isn't allowed" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "055b 444 285"
+  assert_success
+  assert_output "false"
+}
+
+@test "using ascii value for doubled non-digit isn't allowed" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< ":9"
+  assert_success
+  assert_output "false"
+}
+
+@test "non-numeric, non-space char in the middle with a sum that's divisible by 10 isn't allowed" {
+  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+  run gawk -f luhn.awk <<< "59%59"
+  assert_success
+  assert_output "false"
+}
diff --git a/awk/reverse-string/run-tests-awk.txt b/awk/reverse-string/run-tests-awk.txt
index 0058d0ca..7e808582 100644
--- a/awk/reverse-string/run-tests-awk.txt
+++ b/awk/reverse-string/run-tests-awk.txt
@@ -15,21 +15,21 @@ gawk: warning: function `assert' defined but never called directly
 gawk: ./awkunit.awk:26: warning: reference to uninitialized variable `_assert_exit'
 
 real	0m0.004s
-user	0m0.002s
-sys	0m0.001s
+user	0m0.001s
+sys	0m0.003s
 
 gawk --lint --file=./reverse-string.awk < /dev/null > /dev/null
 
-real	0m0.003s
+real	0m0.002s
 user	0m0.000s
-sys	0m0.003s
+sys	0m0.002s
 
 gawk --lint --file=./test-cases.awk < /dev/null > /dev/null
 gawk: ./test-cases.awk:8: warning: subscript of array `cases' is null string
 
-real	0m0.004s
+real	0m0.003s
 user	0m0.001s
-sys	0m0.002s
+sys	0m0.001s
 
 exit 0
 
@@ -38,15 +38,15 @@ exit 0
 Running: bats ./test-reverse-string.bats
 1..6
 ok 1 an empty string
-ok 2 a word # skip
-ok 3 a capitalised word # skip
-ok 4 a sentence with punctuation # skip
-ok 5 a palindrome # skip
-ok 6 an even-sized word # skip
+ok 2 a word
+ok 3 a capitalised word
+ok 4 a sentence with punctuation
+ok 5 a palindrome
+ok 6 an even-sized word
 
-real	0m0.267s
-user	0m0.153s
-sys	0m0.141s
+real	0m0.269s
+user	0m0.177s
+sys	0m0.112s
 
 exit 0
 
@@ -111,9 +111,9 @@ Test 9:
 
 9 out of 9 tests passed!
 
-real	0m0.006s
-user	0m0.003s
-sys	0m0.003s
+real	0m0.004s
+user	0m0.004s
+sys	0m0.001s
 
 Tests Passed!
 
@@ -123,9 +123,9 @@ exit 0
 
 Running: misspell .
 
-real	0m0.035s
-user	0m0.040s
-sys	0m0.014s
+real	0m0.029s
+user	0m0.033s
+sys	0m0.011s
 
 ===============================================================================
 
diff --git a/awk/submit_files b/awk/submit_files
new file mode 100755
index 00000000..86d62b61
--- /dev/null
+++ b/awk/submit_files
@@ -0,0 +1,19 @@
+#!/bin/bash
+
+if [[ ! -d .exercism ]]; then
+	printf "ERROR: Run from inside a project directory.\n\n"
+	exit 1
+fi
+
+declare package_name_kebab
+
+get_awk_package_name() {
+	# these are kebab-case
+	basename "${PWD}"
+} # get_awk_package_name()
+
+package_name_kebab="$(get_awk_package_name)"
+
+echo Running: exercism submit "${package_name_kebab}.awk" "${package_name_kebab}_test.awk" test-cases.awk run-tests-awk.txt
+time exercism submit "${package_name_kebab}.awk" "${package_name_kebab}_test.awk" test-cases.awk run-tests-awk.txt
+printf "\n"
diff --git a/awk/two-fer/run-tests-awk.txt b/awk/two-fer/run-tests-awk.txt
index 81d723b2..b4b87f57 100644
--- a/awk/two-fer/run-tests-awk.txt
+++ b/awk/two-fer/run-tests-awk.txt
@@ -14,9 +14,9 @@ gawk: warning: function `assertEquals' defined but never called directly
 gawk: warning: function `assert' defined but never called directly
 gawk: ./awkunit.awk:26: warning: reference to uninitialized variable `_assert_exit'
 
-real	0m0.003s
-user	0m0.001s
-sys	0m0.001s
+real	0m0.002s
+user	0m0.002s
+sys	0m0.000s
 
 gawk --lint --file=./test-cases.awk < /dev/null > /dev/null
 gawk: ./test-cases.awk:8: warning: subscript of array `cases' is null string
@@ -28,8 +28,8 @@ sys	0m0.001s
 gawk --lint --file=./two-fer.awk < /dev/null > /dev/null
 gawk: ./two-fer.awk:16: warning: reference to uninitialized field `$0'
 
-real	0m0.001s
-user	0m0.001s
+real	0m0.002s
+user	0m0.002s
 sys	0m0.000s
 
 exit 0
@@ -39,13 +39,13 @@ exit 0
 Running: bats ./test-two-fer.bats
 1..4
 ok 1 no file given
-ok 2 empty file given # skip
-ok 3 a name given # skip
-ok 4 name with a space # skip
+ok 2 empty file given
+ok 3 a name given
+ok 4 name with a space
 
-real	0m0.200s
-user	0m0.111s
-sys	0m0.104s
+real	0m0.209s
+user	0m0.129s
+sys	0m0.102s
 
 exit 0
 
@@ -81,9 +81,9 @@ Test 6:
     result -> passed
 
 
-real	0m0.008s
-user	0m0.001s
-sys	0m0.008s
+real	0m0.006s
+user	0m0.004s
+sys	0m0.002s
 
 Tests Passed!
 
@@ -93,8 +93,8 @@ exit 0
 
 Running: misspell .
 
-real	0m0.037s
-user	0m0.042s
+real	0m0.031s
+user	0m0.024s
 sys	0m0.019s
 
 ===============================================================================