Рейтинг@Mail.ru

Наши друзья и партнеры

купить дешевый 
компьютер родом из Dhgate.com






Книги по Linux (с отзывами читателей)

Библиотека сайта rus-linux.net

9.2. Managing Processes

From time to time you may wish to view processes that are running on Linux. To obtain a list of these processes, type ``ps -aux'', which will look similar to the following:

USER       PID %CPU %MEM  SIZE   RSS TTY STAT START   TIME COMMAND
bin         69  0.0  1.0   788   320  ?  S   Nov 30   0:00 /usr/sbin/rpc.portmap
frampton 10273  0.0  2.1  1136   664  p0 S    14:12   0:00 -bash
frampton 10744  0.0  1.1   820   360  p0 R    17:25   0:00 ps -aux
frampton 10745  0.0  0.8   788   264  p0 S    17:25   0:00 more
nobody   10132  0.0  1.8  1016   588  ?  S    13:36   0:00 httpd
nobody   10133  0.0  1.8   988   568  ?  S    13:36   0:00 httpd
nobody   10413  0.0  1.8  1012   580  ?  S    14:56   0:00 httpd
nobody   10416  0.0  1.8  1012   580  ?  S    14:56   0:00 httpd
nobody   10418  0.0  1.8  1012   588  ?  S    14:57   0:00 httpd
nobody   10488  0.0  1.7   976   556  ?  S    15:34   0:00 httpd
nobody   10564  0.0  1.8   988   564  ?  S    16:06   0:00 httpd
nobody   10600  0.0  1.8   988   564  ?  S    16:15   0:00 httpd
nobody   10670  0.0  1.8   988   568  ?  S    16:45   0:00 httpd
nobody   10704  0.0  1.7   976   552  ?  S    17:03   0:00 httpd
root         1  0.0  1.0   776   312  ?  S   Nov 30   1:13 init [3]
root         2  0.0  0.0     0     0  ?  SW  Nov 30   0:00 (kflushd)
root         3  0.0  0.0     0     0  ?  SW  Nov 30   0:00 (kswapd)

The list shows you the owner of the process ("nobody" for special services such as web servers), the process identification number, the % of CPU time the process is currently using, the % of memory the process is consuming, and other related information, as well as a description of the task itself.

To get more information on a given process, type ``ps pid'' (where "pid" is the process identification number). Looking at our example above, "ps 10704" would display:

10704  ?  S     0:00 /usr/local/etc/httpd/httpd

This would tell you that this particular process is a web server (the Apache web server appears multiple times in the process list; for information on why see Section 7.1).

If you happen to notice a service is not operating, you can use the "kill -HUP pid" (where "pid" is the process identification number as shown in the process list produced with "ps"). For example, if Internet services (a process called inetd, process #123 in our example) are not working as they should, a ``kill -HUP 123'' (or even safer, use the ``killall'' command and specify the process name: ``killall -HUP inetd'') should restart the process. The -HUP option to the kill command means "hang up"; the process knows that it is supposed to reload itself.

Another thing to try if you are unable to resolve the problem would be to shut the system down and reboot it (see Section 6.7 for details).

At times, you may find it necessary to temporarily suspend a process, and then resume its execution at a later time. For example, you may be running a CPU-intensive job and wish to burn an IDE-based CDRecordable. Since IDE-based devices rely on the CPU for much of the work behind input/output, they are prone to buffer starvation if your CPU is too busy, and you end up with a useless coaster instead of a properly prepared CD! The following two commands will suspend a process, and the resume it, respectively:

kill -STOP 945
kill -CONT 945

Red Hat provides a better way of starting and stopping some processes, which are covered in Section 9.3 below.

Если вам понравилась статья, поделитесь ею с друзьями: