top
Reading the systemPackage: procps
The live state of processes, refreshed. Useful for what is consuming now; useless for what was consuming an hour ago, which only sar kept.
What its options do in the lessons
From the same glossary the lessons render under their commands, so the two cannot disagree.
top -o- Sorts on the named column (
-o %MEMfor memory) rather than on CPU. top -b- Batch mode:
topaccepts no input and ends after the number of frames set with-n. The form you redirect into a file or paste into a ticket. top -n- How many frames top produces before it ends. Two at least when the processor line is what you came for: it covers the interval since the previous frame.
top -d- The delay between refreshes, in seconds. In batch mode it is the length of the interval the percentages are computed over.