#!/bin/bash
s="123john456:x:98:98::/home/john123:/bin/bash
john123:x:98:98::/home/john123:/bin/bash"
awk -F ':' '{n=split($1, a, /[^0-9]+/); b=0; for (i=1;i<=n;i++) { b += a[i]; }; print b; }' <<< "$s"
IyEvYmluL2Jhc2gKcz0iMTIzam9objQ1Njp4Ojk4Ojk4OjovaG9tZS9qb2huMTIzOi9iaW4vYmFzaApqb2huMTIzOng6OTg6OTg6Oi9ob21lL2pvaG4xMjM6L2Jpbi9iYXNoIgphd2sgLUYgJzonICd7bj1zcGxpdCgkMSwgYSwgL1teMC05XSsvKTsgYj0wOyBmb3IgKGk9MTtpPD1uO2krKykgeyBiICs9IGFbaV07IH07IHByaW50IGI7IH0nIDw8PCAiJHMi