How can I measure the actual memory usage of an application or process?

Question

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How do you measure the memory usage of an application or process in Linux?

From the blog articl

Answer 1

A good test of the more "real world" usage is to open the application, run vmstat -s, and check the "active memory" statistic. Close the application, wait a few seconds, and run vmstat -s again.

However much active memory was freed was in evidently in use by the application.