Disk activity monitoring: iostat options

       -o, --only
              Only show processes or threads actually doing I/O, 

              instead of showing all processes or threads. 

              This can be dynamically toggled by pressing o.

       -b, --batch
              Turn on non-interactive mode.  Useful for logging I/O usage over time.

       -n NUM, --iter=NUM
              Set the number of iterations before quitting (never quit by default).

              This is most useful in non-interactive mode.

       -d SEC, --delay=SEC
              Set the delay between iterations in seconds (1 second by default).

              Accepts non-integer values such as 1.1 seconds.

       -p PID, --pid=PID
              A list of processes/threads to monitor (all by default).

       -u USER, --user=USER
              A list of users to monitor (all by default)

       -P, --processes
              Only show processes. Normally iotop shows all threads.

       -a, --accumulated
              Show accumulated I/O instead of bandwidth.

              In this mode, iotop shows the amount of I/O processes have done 

              since iotop started.

       -k, --kilobytes
              Use  kilobytes instead of a human friendly unit.

              This mode is useful when scripting the batch mode of iotop.

              Instead of choosing the most appropriate unit iotop will dis‐
              play all sizes in kilobytes.

       -t, --time
              Add a timestamp on each line (implies --batch).

              Each line will be prefixed by the current time.

       -q, --quiet
              suppress some lines of header (implies --batch).

              This option can be specified up to three times to remove header lines.
              -q     column names are only printed on the first iteration,
              -qq    column names are never printed,
              -qqq   the I/O summary is never printed.