题解 | #格式化输出#

#!/bin/bash
#太复杂了，别学我
for i in `cat nowcoder.txt`
do
    b=${#i}
    if [[ $b < 4 ]]
    then
        echo $i;
    fi

    if [[ $b > 3 ]]
    then
        a=$(($b % 3))
        if [[ $a = 1 ]]
        then
            sum1=""
            for ((a=-3;a>-b;a=a-3))
            do
                sum=",""${i:a:3}"
                sum1="$sum""$sum1"
            done
            echo "1""$sum1"
        
        elif [[ $a = 2 ]]
        then
            sum1=""
            for ((a=-3;a>-b;a=a-3))
            do
                sum=",""${i:a:3}"
                sum1="$sum""$sum1"
            done
            echo "12""$sum1"
        else
            sum1=""
            for ((a=-3;a>-b;a=a-3))
            do
                sum=",""${i:a:3}"
                sum1="$sum""$sum1"
            done
            echo "123""$sum1"
        fi
    fi
done