#!/bin/bash

awk -F '[1,2,3,4,5]' 'BEGIN{sum=0}{
    for (i=1;i<=NR;++i){if (i==NR){
        print "line"i" number: "NF-1;sum+=NF-1
        }  
    }
}END{print "sum is "sum}' ./nowcoder.txt

-F '[1,2,3,4,5]' 指定分隔符为1,2,3,4,5

if (i==NR) 当行号与循环的i对应,即在同一行时执行括号内命令(因为NR是1,2,3,4,不限制会进行多次循环)