shell使用for循环

arr=('html' 'JavaScript' 'css')
for i in ${!arr[*]}
do
  echo ${arr[i]}
done

arr=('html' 'JavaScript' 'css')
for value in ${arr[*]}
do
  echo $value
done

awk 'BEGIN{for(i=1; i<=10; i++) print i}'

for i in $(seq 1 10)  
do   
echo $(expr $i \* 3 + 1);  
done   

for i in {1..10}
do
echo $(expr $i \* 3 + 1);
done

for((i=1;i<=10;i++));  
do
echo $(expr $i \* 3 + 1);
done

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