How to create a script for loop print ps information

Just as title mentioned, How can I oversee a process using ps with periodicity scanning just like command "top", thanks first开发者_StackOverflow:)

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If the process you want to see is PID 4815 and you want it to update every 2 seconds you could do an infinite while loop.

while true; do ps 4815; sleep 2; clear; done

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The utility watch is meant for this purpose also:

watch ps 4815