"if my question is slightly non-Perl....

No, your question is entirely non-Perl; in fact, somewhat akin to:

"I'm cooking a turkey for dinner. Please provide a synopsis of Turkish history"

As to "tons of searchs," didn't you find man proc referenced somewhere... or the documentation itself, http://linux.die.net/man/5/proc?

man proc will tell you, among other things:

/proc/pid/stat
Status information about the process. This is used by ps(1). It is defined in /usr/src/linux/fs/proc/array.c.
The fields, in order, with their proper scanf(3) format specifiers, are:
....

Update: If you don't Read The Fine Manual, you really shouldn't expect the Monks to do your reading, interpretation and coding for you. See On asking for help and How do I post a question effectively?

In reply to Re^3: (OT) Get the number of blocks per second by reading the proc diskstats file by ww
in thread (OT) Get the number of blocks per second by reading the proc diskstats file by haavard82

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