diff --git a/config.json b/config.json
index 277158e2..2c61446a 100644
--- a/config.json
+++ b/config.json
@@ -182,6 +182,14 @@
           "input_validation"
         ]
       },
+      {
+        "slug": "line-up",
+        "name": "Line Up",
+        "uuid": "72318e58-23d7-4b82-a4ee-dbbee4c4f000",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "pangram",
         "name": "Pangram",
diff --git a/exercises/practice/line-up/.docs/instructions.md b/exercises/practice/line-up/.docs/instructions.md
new file mode 100644
index 00000000..fb41d4cb
--- /dev/null
+++ b/exercises/practice/line-up/.docs/instructions.md
@@ -0,0 +1,19 @@
+# Instructions
+
+Given a name and a number, your task is to produce a sentence using that name and that number as an [ordinal numeral][ordinal-numeral].
+Yaʻqūb expects to use numbers from 1 up to 999.
+
+Rules:
+
+- Numbers ending in 1 (except for 11) → `"st"`
+- Numbers ending in 2 (except for 12) → `"nd"`
+- Numbers ending in 3 (except for 13) → `"rd"`
+- All other numbers → `"th"`
+
+Examples:
+
+- `"Mary", 1` → `"Mary, you are the 1st customer we serve today. Thank you!"`
+- `"John", 12` → `"John, you are the 12th customer we serve today. Thank you!"`
+- `"Dahir", 162` → `"Dahir, you are the 162nd customer we serve today. Thank you!"`
+
+[ordinal-numeral]: https://en.wikipedia.org/wiki/Ordinal_numeral
diff --git a/exercises/practice/line-up/.docs/introduction.md b/exercises/practice/line-up/.docs/introduction.md
new file mode 100644
index 00000000..ea07268a
--- /dev/null
+++ b/exercises/practice/line-up/.docs/introduction.md
@@ -0,0 +1,7 @@
+# Introduction
+
+Your friend Yaʻqūb works the counter at a deli in town, slicing, weighing, and wrapping orders for a line of hungry customers that gets longer every day.
+Waiting customers are starting to lose track of who is next, so he wants numbered tickets they can use to track the order in which they arrive.
+
+To make the customers feel special, he does not want the ticket to have only a number on it.
+They shall get a proper English sentence with their name and number on it.
diff --git a/exercises/practice/line-up/.meta/config.json b/exercises/practice/line-up/.meta/config.json
new file mode 100644
index 00000000..5905f1e3
--- /dev/null
+++ b/exercises/practice/line-up/.meta/config.json
@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "line_up.sh"
+    ],
+    "test": [
+      "line_up.bats"
+    ],
+    "example": [
+      ".meta/example.sh"
+    ]
+  },
+  "blurb": "Help lining up customers at Yaʻqūb's Deli.",
+  "source": "mk-mxp, based on previous work from Exercism contributors codedge and neenjaw",
+  "source_url": "https://forum.exercism.org/t/new-exercise-ordinal-numbers/19147"
+}
diff --git a/exercises/practice/line-up/.meta/example.sh b/exercises/practice/line-up/.meta/example.sh
new file mode 100644
index 00000000..764b560f
--- /dev/null
+++ b/exercises/practice/line-up/.meta/example.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+ordinal() {
+    case $1 in
+        *11|*12|*13) echo "${1}th" ;;
+        *1) echo "${1}st" ;;
+        *2) echo "${1}nd" ;;
+        *3) echo "${1}rd" ;;
+        *) echo "${1}th" ;;
+    esac
+}
+
+main() {
+    printf "%s, you are the %s customer we serve today. Thank you!" "$1" "$(ordinal "$2")"
+}
+
+main "$@"
diff --git a/exercises/practice/line-up/.meta/tests.toml b/exercises/practice/line-up/.meta/tests.toml
new file mode 100644
index 00000000..36fdf1d0
--- /dev/null
+++ b/exercises/practice/line-up/.meta/tests.toml
@@ -0,0 +1,67 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[7760d1b8-4864-4db4-953b-0fa7c047dbc0]
+description = "format smallest non-exceptional ordinal numeral 4"
+
+[e8b7c715-6baa-4f7b-8fb3-2fa48044ab7a]
+description = "format greatest single digit non-exceptional ordinal numeral 9"
+
+[f370aae9-7ae7-4247-90ce-e8ff8c6934df]
+description = "format non-exceptional ordinal numeral 5"
+
+[37f10dea-42a2-49de-bb92-0b690b677908]
+description = "format non-exceptional ordinal numeral 6"
+
+[d8dfb9a2-3a1f-4fee-9dae-01af3600054e]
+description = "format non-exceptional ordinal numeral 7"
+
+[505ec372-1803-42b1-9377-6934890fd055]
+description = "format non-exceptional ordinal numeral 8"
+
+[8267072d-be1f-4f70-b34a-76b7557a47b9]
+description = "format exceptional ordinal numeral 1"
+
+[4d8753cb-0364-4b29-84b8-4374a4fa2e3f]
+description = "format exceptional ordinal numeral 2"
+
+[8d44c223-3a7e-4f48-a0ca-78e67bf98aa7]
+description = "format exceptional ordinal numeral 3"
+
+[6c4f6c88-b306-4f40-bc78-97cdd583c21a]
+description = "format smallest two digit non-exceptional ordinal numeral 10"
+
+[e257a43f-d2b1-457a-97df-25f0923fc62a]
+description = "format non-exceptional ordinal numeral 11"
+
+[bb1db695-4d64-457f-81b8-4f5a2107e3f4]
+description = "format non-exceptional ordinal numeral 12"
+
+[60a3187c-9403-4835-97de-4f10ebfd63e2]
+description = "format non-exceptional ordinal numeral 13"
+
+[2bdcebc5-c029-4874-b6cc-e9bec80d603a]
+description = "format exceptional ordinal numeral 21"
+
+[74ee2317-0295-49d2-baf0-d56bcefa14e3]
+description = "format exceptional ordinal numeral 62"
+
+[b37c332d-7f68-40e3-8503-e43cbd67a0c4]
+description = "format exceptional ordinal numeral 100"
+
+[0375f250-ce92-4195-9555-00e28ccc4d99]
+description = "format exceptional ordinal numeral 101"
+
+[0d8a4974-9a8a-45a4-aca7-a9fb473c9836]
+description = "format non-exceptional ordinal numeral 112"
+
+[06b62efe-199e-4ce7-970d-4bf73945713f]
+description = "format exceptional ordinal numeral 123"
diff --git a/exercises/practice/line-up/bats-extra.bash b/exercises/practice/line-up/bats-extra.bash
new file mode 100644
index 00000000..54d48070
--- /dev/null
+++ b/exercises/practice/line-up/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/exercises/practice/line-up/line_up.bats b/exercises/practice/line-up/line_up.bats
new file mode 100644
index 00000000..5dde8745
--- /dev/null
+++ b/exercises/practice/line-up/line_up.bats
@@ -0,0 +1,154 @@
+#!/usr/bin/env bats
+load bats-extra
+
+@test "format smallest non-exceptional ordinal numeral 4" {
+    #[[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Gianna" 4
+
+    assert_success
+    assert_output "Gianna, you are the 4th customer we serve today. Thank you!"
+}
+
+@test "format greatest single digit non-exceptional ordinal numeral 9" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Maarten" 9
+
+    assert_success
+    assert_output "Maarten, you are the 9th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 5" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Petronila" 5
+
+    assert_success
+    assert_output "Petronila, you are the 5th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 6" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Attakullakulla" 6
+
+    assert_success
+    assert_output "Attakullakulla, you are the 6th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 7" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Kate" 7
+
+    assert_success
+    assert_output "Kate, you are the 7th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 8" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Maximiliano" 8
+
+    assert_success
+    assert_output "Maximiliano, you are the 8th customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 1" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Mary" 1
+
+    assert_success
+    assert_output "Mary, you are the 1st customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 2" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Haruto" 2
+
+    assert_success
+    assert_output "Haruto, you are the 2nd customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 3" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Henriette" 3
+
+    assert_success
+    assert_output "Henriette, you are the 3rd customer we serve today. Thank you!"
+}
+
+@test "format smallest two digit non-exceptional ordinal numeral 10" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Alvarez" 10
+
+    assert_success
+    assert_output "Alvarez, you are the 10th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 11" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Jacqueline" 11
+
+    assert_success
+    assert_output "Jacqueline, you are the 11th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 12" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Juan" 12
+
+    assert_success
+    assert_output "Juan, you are the 12th customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 13" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Patricia" 13
+
+    assert_success
+    assert_output "Patricia, you are the 13th customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 21" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Washi" 21
+
+    assert_success
+    assert_output "Washi, you are the 21st customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 62" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Nayra" 62
+
+    assert_success
+    assert_output "Nayra, you are the 62nd customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 100" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "John" 100
+
+    assert_success
+    assert_output "John, you are the 100th customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 101" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Zeinab" 101
+
+    assert_success
+    assert_output "Zeinab, you are the 101st customer we serve today. Thank you!"
+}
+
+@test "format non-exceptional ordinal numeral 112" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Knud" 112
+
+    assert_success
+    assert_output "Knud, you are the 112th customer we serve today. Thank you!"
+}
+
+@test "format exceptional ordinal numeral 123" {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+    run bash line_up.sh "Yma" 123
+
+    assert_success
+    assert_output "Yma, you are the 123rd customer we serve today. Thank you!"
+}
diff --git a/exercises/practice/line-up/line_up.sh b/exercises/practice/line-up/line_up.sh
new file mode 100644
index 00000000..960869f3
--- /dev/null
+++ b/exercises/practice/line-up/line_up.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+# The following comments should help you get started:
+# - Bash is flexible. You may use functions or write a "raw" script.
+#
+# - Complex code can be made easier to read by breaking it up
+#   into functions, however this is sometimes overkill in bash.
+#
+# - You can find links about good style and other resources
+#   for Bash in './README.md'. It came with this exercise.
+#
+#   Example:
+#   # other functions here
+#   # ...
+#   # ...
+#
+#   main () {
+#     # your main function code here
+#   }
+#
+#   # call main with all of the positional arguments
+#   main "$@"
+#
+# *** PLEASE REMOVE THESE COMMENTS BEFORE SUBMITTING YOUR SOLUTION ***