本文主要介绍linux中的ps命令的相关用法。
1 概述
ps命令的作用：report a snapshot of the current processes.
2 常见用法
2.1 常用选项
-e： Select all processes. Identical to -A.
-f：does full-format listing. This option can be combined with many other UNIX-style options to add additional columns. It also causes the command arguments to be printed. When used with -L, the NLWP (number of threads) and LWP (thread ID) columns will be added. See the c option, the format keyword args, and the format keyword comm.
2.2 关键字及描述
p -- pid -- process ID
P -- ppid -- parent ID
说明：在 linux 中，使用 ps 打印进程及线程信息时， 实际上 PID 表示线程信息，而 PPID 表示该线程所属的进程信息。如下：
Suse-116:~ # ps -efL |head -1;ps -efL|grep agency_server
UID PID PPID LWP C NLWP STIME TTY TIME CMD
root 2078 14610 2078 0 1 Jul12 ? 00:00:00 agency_server 63 0 8011 /usr/local/middle/log/agency_server/agency_server 10000000 20
root 2079 14610 2079 0 1 Jul12 ? 00:00:00 agency_server 63 1 8011 /usr/local/middle/log/agency_server/agency_server 10000000 20
root 32581 25137 32581 0 1 09:53 pts/0 00:00:00 grep --color agency_server
Suse-116:~ # 从上述打印结果就能看到，线程 LWP（轻量级进程）与 PID 一致。这也符合上述说明。
2.3 打印标题信息
用法：ps -ef|head -1;ps -ef|grep 进程名
示例如下：
Suse-116:~ # ps -ef|head -1;ps -ef|grep agency_server
UID PID PPID C STIME TTY TIME CMD
root 2078 14610 0 Jul12 ? 00:00:00 agency_server 63 0 8011 /usr/local/middle/log/agency_server/agency_server 10000000 20
root 2079 14610 0 Jul12 ? 00:00:00 agency_server 63 1 8011 /usr/local/middle/log/agency_server/agency_server 10000000 20
root 29203 29029 0 09:26 pts/3 00:00:00 grep --color agency_server
Suse-116:~ #