Solved leap in Bash

bash/leap/leap.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+year=$1
+
+if [ $# -ne 1 ] || ! [[ $1 =~ ^[0-9]+$ ]]; then
+    echo "Usage: leap.sh <year>"
+    exit 1
+fi
+
+if (( year % 4 == 0 && year % 100 != 0 )) || (( year % 400 == 0 )); then
+    echo "true"
+else
+    echo "false"
+fi