Add command-line options to add-exercise script. (#149)

Additional shellcheck suggestions.

bin/add-exercise

@@ -1,12 +1,14 @@
 #!/usr/bin/env bash
 
 set -euo pipefail
+scriptname=$0
 
-if (( $# < 1 )); then
+help_and_exit() {
     echo >&2 "Populates a new directory for a practice exercise."
-    echo >&2 "Usage: $0 <exercise-slug> [author]"
+    echo >&2 "Usage: ${scriptname} [-h] [-a author] <exercise-slug>"
+    echo >&2 "Where: author is the github username of the exercise creator."
     exit 1
-fi
+}
 
 die() { echo >&2 "$*"; exit 1; }
 
@@ -14,11 +16,24 @@ required_tool() {
     command -v "$1" >/dev/null 2>&1 ||
         die "$1 is required but not installed. Please install it and make sure it's in your PATH."
 }
+
+(( $# >= 1 )) || help_and_exit
+
 required_tool jq
 required_tool curl
 
 [[ -f ./bin/fetch-configlet ]] || die "run this script from the repo's root directory."
 
+author=''
+while getopts :ha: opt; do
+    case $opt in
+        h) help_and_exit ;;
+        a) author=$OPTARG ;;
+        ?) echo >&2 "Unknown option: -$OPTARG"; help_and_exit ;;
+    esac
+done
+shift "$((OPTIND - 1))"
+
 slug="${1}"
 
 # Create entry for exercise in config.json and exercise files
@@ -39,11 +54,9 @@ end-of-tests
 ;with
 END_TEST
 
-if (( $# < 2 )); then
+if [[ -z $author ]]; then
     echo
     read -rp 'Your github username: ' author
-else
-    author="${2}"
 fi
 
 conf="exercises/practice/${slug}/.meta/config.json"
@@ -64,5 +77,5 @@ Your next steps are:
 - Verify the example solution by running 'bin/test-no-docker ${slug}'
 - Create the stub solution in 'exercises/practice/${slug}/${slug}.8th'
 - Update the 'difficulty' value for the exercise's entry in the 'config.json' file
-- Validate CI using 'bin/configlet lint'
+- Validate CI using 'bin/configlet lint' and 'bin/configlet fmt'
 NEXT_STEPS

bin/test

@@ -24,7 +24,7 @@ function run_test_runner() {
 }
 
 function verify_exercise() {
-    local dir=$(realpath $1)
+    local dir=$(realpath "$1")
     local slug=$(basename "${dir}")
     local implementation_file_key=$2    
     local implementation_file=$(jq -r --arg d "${dir}" --arg k "${implementation_file_key}" '$d + "/" + .files[$k][0]' "${dir}/.meta/config.json")
@@ -49,18 +49,18 @@ function verify_exercise() {
 
 # Verify the Concept Exercises
 for concept_exercise_dir in ./exercises/concept/*/; do
-    if [ -d $concept_exercise_dir ]; then
+    if [[ -d $concept_exercise_dir ]]; then
         echo "Checking $(basename "${concept_exercise_dir}") exercise..."
-        verify_exercise $concept_exercise_dir "exemplar"
+        verify_exercise "$concept_exercise_dir" "exemplar"
     fi
 done
 
 # Verify the Practice Exercises
 for practice_exercise_dir in ./exercises/practice/*/; do
-    if [ -d $practice_exercise_dir ]; then
+    if [[ -d $practice_exercise_dir ]]; then
         echo "Checking $(basename "${practice_exercise_dir}") exercise..."
-        verify_exercise $practice_exercise_dir "example"
+        verify_exercise "$practice_exercise_dir" "example"
     fi
 done
 
-exit ${exit_code}
+exit "${exit_code}"

bin/test-no-docker

@@ -15,7 +15,7 @@ make_test_dir() {
     local slug=${exercise_dir##*/}
     local key=$2
     (
-        cd "$exercise_dir"
+        cd "$exercise_dir" || die "cannot cd to: $exercise_dir"
         [[ -f test-words.8th ]] && cp test-words.8th "$test_dir"
         [[ -d libs ]] && cp -r libs "$test_dir"
         while IFS= read -r test; do