循环
20191025
whlie
s=0
i=1
while [[ i < 4 ]]
do
s=(( $s + $i ))
i=(( $i + 1 ))
done
echo $s # 输出:6
for
s=0
nu=4
for (( i = 1; i < $nu; i++ ))
do
s=$(( $s + $i ))
done
echo $s # 输出:6
continue
break
filename="my.txt" # 文件内容:-2 -1 0 1 2 3 4 5 6 (列存储)
s=0
for line in `cat $filename`
do
let line=$line
if [ $line -le 0 ] #if [[ $line < 0 ]] (出错???,不能跳过小于0的数值)
then
continue
fi
if [[ $line = 4 ]] #if [[ $line == 4 ]](正确,可以退出循环???)
then
break
fi
echo $line
s=$(( $s + $line ))
done
echo $s # 输出:6