Open a cache of riches with lsof

Top

Pressing r ("renice") changes the "nice" value of a process, which determines its priority. A lower nice value means a high priority. Possible values range from -20 to 19. To do this, you must specify the process ID (PID) and the nice value. Because the process order constantly changes to reflect the CPU utilization in this view, it is difficult to read the PID of a process from the table given a default refresh interval of three seconds. Pressing d or s sets a different interval, for example, 10 seconds. You can also send a signal to the process with k ("kill," see Table 3). Without further instructions, Top sends the signal SIGTERM, which instructs the process to exit.

Table 2

Process States

Abbreviation

Status

Meaning

D

Delay

The process is sleeping, waiting in a system call, without the ability to interrupt, typically for an I/O request. ps aux | grep "[D]" shows which processes are affected for wait I/O.

R

Running

The process is running or was just running.

S

Sleeping

The process is sleeping, waiting, with the ability to interrupt  – for example, for a response to a network request, a request from another process, or user input.

T

Traced

The process has been stopped – for example, to step through it with a debugger.

Z

Zombie

The process has terminated, and the kernel is still waiting for the parent process to pick up its return value.

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