shfmt create_files.sh and fix for macOS

Author: gchan

create_files.sh

@@ -2,20 +2,19 @@
 
 DIR=$(dirname $(readlink -f $0))
 
-for y in `seq -w 2015 2024`; do
+for y in $(seq -w 2015 2024); do
   mkdir $DIR/$y
 
-  for i in `seq -w 1 25`; do
+  for i in $(seq -w 1 25); do
     mkdir $DIR/$y/day-$i
 
     if [ -z "$(ls -A $DIR/$y/day-$i)" ]; then
       cp template.rb $DIR/$y/day-$i/day-$i-part-1.rb
 
-      if [ $i -ne '25' ]
-      then
+      if [ $i -ne '25' ]; then
         cp template.rb $DIR/$y/day-$i/day-$i-part-2.rb
       fi
-      sed -i "s/\\$/${i}/g" $DIR/$y/day-$i/*.rb
+      sed -i "" "s/\\$/${i}/g" $DIR/$y/day-$i/*.rb
 
       touch $DIR/$y/day-$i/README.txt
       touch $DIR/$y/day-$i/day-$i-input.txt