Shell腳本筆記3-循環

for 列表形式

for variable in {list}
do
    statement
done

for var in 1 2 3 4
do
    echo $var
done

for var in {1..4}
do
    echo $var
done

for var in {start..end..step}
do
    statement
done

for i in {1..100..2}
do
    echo $i
done

for file in $(ls)
do
    echo $file
done

for file in *
do
    echo $file
done

類c風格的for循環

for ((expression1;expression2;expression3))
do
    statement
done

for ((i=0;i<5;i++)
do
    echo $i
done

for循環處理數組

for variable in ${array[*]}
do
    statement
done

array={1 2 3 4 5}
for num in ${array[*]}
do
    echo $num
done

until循環，條件滿足後退出

until expression
do
    statement
done

num=1
until [[ num -gt 4 ]]
do
    echo $num
    ((num++)
done

while循環

while expression
do
    statement
done

num=1
while [[ num -lt 5 ]]
do
    echo $num
    let "num++"
done