Day 3 part 1

day-3/script.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+regex="mul\(([0-9]{1,3}),([0-9]{0,3}))"
+
+acc=0
+while read line; do
+    if [[ $line =~ $regex ]] then
+        n1=${BASH_REMATCH[1]}
+        n2=${BASH_REMATCH[2]}
+        acc=$(expr $n1 \* $n2 + $acc)
+    fi
+done <<< $(grep -Eo $regex input.txt)
+echo $acc