New Post: How to deal with the error stream when using ShellStream

da_rinkes wrote:

What is this for?

i < 4

Error output (STDERR) is included in the shell stream.
So your code looks OK, beside the i < 4 test.

thanks for reply
using the following example ,i try to explain why i use “i<4”

for((i=0;i<10;i++));
do 
    echo hello;
    echo $0;
done

my input is "./hello.sh"
without i<4 ,we will see this and it is not correct.

hello
hello
hello
hello
hello
hello
hello
hello
hello

and i can not get stderr when i remove "i<4"