Shell Script学习笔记1:循环表达(for, while, until)

for 循环

for i in {a..z}; do actions; done;

or

for ((i=0;i<10;i++))
{
    commands;
}

注意：第二种表达方式中，for关键字之后必须有空格。

while 循环

while condition
do
    commands;
done

until 循环

until condition
do
    commands;
done