奇数偶数求和运算

#!/bin/bash
sum=0
for ((i=1;i<=10;i+=2))
do
     ((sum+=i))
done
echo sum=$sum

#!/bin/bash
sum=0
for ((i=1;i<=10;i+=2))
do
    let sum+=i
done
echo sum=$sum

#!/bin/bash
sum=0
for ((i=1;i<=10;i++))
do
    if  [  $((i%2)) -eq 1 ]
        then 
               ((sum+=i))
        else
               continue
   fi
done
echo sum=$sum

#!/bin/bash
sum=0
for ((i=1;j<=10;i++))
do
     if [ `expr $i % 2` -eq 1 ]
     then 
           let sum+=$i
     else
           continue
    fi
done
echo sum=$sum

#!/bin/bash
sum=0
for ((i=1;i<=10;i++))
do
     if [ $((i%2)) -eq 0 ]
     then 
               ((sum+=i))
     else
               continue
    fi
done
echo sum=$sum 

#!/bin/bash
sum=0
for ((i=1;i<=10;i++))
do
    if [  `expr $i % 2` -eq 0 ]
    then 
           let sum+=i
    else
          continue
    fi
done
echo sum=$sum