Refactor date calculation in create_post.sh for compatibility with macOS and Linux

Author: mrbiggred

create_post.sh

@@ -1,17 +1,21 @@
 #!/bin/bash
 
 # Calculate the next Tuesday (or today if it's Tuesday)
-# In Linux date, weekday: 0=Sunday, 1=Monday, ..., 6=Saturday
 current_weekday=$(date +%w)              # 0=Sun ... 6=Sat
 days_to_tuesday=$(( (2 - current_weekday + 7) % 7 ))
 
-# If today is Tuesday, days_to_tuesday will be 0 → perfect
-# Add the calculated days
-tuesday=$(date -d "+${days_to_tuesday} days" +%Y-%m-%d)
-
-year=$(date -d "$tuesday" +%Y)
-month=$(date -d "$tuesday" +%02m)
-day=$(date -d "$tuesday" +%02d)
+# Add the calculated days (compatible with both macOS and Linux)
+if date -v +0d &>/dev/null; then
+  # macOS (BSD date)
+  tuesday=$(date -v "+${days_to_tuesday}d" +%Y-%m-%d)
+else
+  # Linux (GNU date)
+  tuesday=$(date -d "+${days_to_tuesday} days" +%Y-%m-%d)
+fi
+
+year=${tuesday%%-*}                       # 2026
+month=${tuesday#*-}; month=${month%-*}    # 02
+day=${tuesday##*-}                        # 24
 
 # Define paths
 folder_path="docs/posts/$year/$month/$day"