When we talk about "time" on UNIX systems, we could be talking about
What time it is, as shown by the
command, and recorded in
countless ways - as file creation and modification times, as the time
of last login, and so on.
How long things take.
This chapter is concerned with the latter. It talks about how long
programs take to run, what makes them faster or slower, and what you
can (or more often can't) do about it.