June 2018 Update

Task/Digital-root/UNIX-Shell/digital-root.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+numbers=(627615 39390 588225 393900588225 55)
+declare root
+
+for number in "${numbers[@]}"; do
+    declare -i iterations
+    root="${number}"
+    while [[ "${#root}" -ne 1 ]]; do
+        root="$(( $(fold -w1 <<<"${root}" | xargs | sed 's/ /+/g') ))"
+        iterations+=1
+    done
+    echo -e "${number} has additive persistence ${iterations} and digital root ${root}"
+    unset iterations
+done | column -t