Thank you your reply. The article is very detail. I know Buffering will give me the feeling of the dalaying, but the magical thing is: I called time() or Time::HiRes method before pipe call to capture the timestamp before the pipe opened, then I capture another timestamp after the pipe closed; while the program itself will display a time of execution as well. I found the time shown in perl is always less than the time shown in the pipe result largely......I checked the documentation and I am quite sure the time unit is correct and the method I used to get the interval is from the sample code, so I don't think this is the buffering problem...any idea?

In reply to Re^2: Print the output from the pipe while waiting by Anonymous Monk
in thread Print the output from the pipe while waiting by Anonymous Monk

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