const data = `1.52.0.0 -- 1.55.255.255
14.0.16.0 -- 14.0.31.255
123.15.0.1 -- 123.15.0.255`

let result = '';
data.split('\n').map((item, index) => {
const ips = item.split(' -- ');
result += `
edit ${index+1}
        set start-ip ${ips[0]}
        set end-ip ${ips[1]}
    next
`
});
console.log(result);