Linux 基本工具(ps)
ps 命令用于展示进程信息，在查看进程是否存在，或者进程的启动命令，或者是进程运行环境信息。
查看所有进程， 仅包含进程名称
root@server:~# ps -e
PID TTY TIME CMD
1 ? 00:00:02 systemd
2 ? 00:00:00 kthreadd
3 ? 00:00:00 ksoftirqd/0
5 ? 00:00:00 kworker/0:0H
7 ? 00:01:49 rcu_sched
8 ? 00:00:00 rcu_bh
9 ? 00:00:00 migration/0
10 ? 00:00:01 watchdog/0
11 ? 00:00:01 watchdog/1
12 ? 00:00:00 migration/1
13 ? 00:00:01 ksoftirqd/1
15 ? 00:00:00 kworker/1:0H
16 ? 00:00:01 watchdog/2
17 ? 00:00:00 migration/2
18 ? 00:00:00 ksoftirqd/2
20 ? 00:00:00 kworker/2:0H
21 ? 00:00:00 watchdog/3
22 ? 00:00:00 migration/3
23 ? 00:00:00 ksoftirqd/3
25 ? 00:00:00 kworker/3:0H
26 ? 00:00:00 kdevtmpfs
......-e选项意味选择所有进程
查看所有进程，包括命名参数，并显示父进程编号
root@server:~# ps -ef
UID PID PPID C STIME TTY TIME CMD
root 1 0 0 Aug27 ? 00:00:02 /sbin/init
root 2 0 0 Aug27 ? 00:00:00 [kthreadd]
root 3 2 0 Aug27 ? 00:00:00 [ksoftirqd/0]
root 5 2 0 Aug27 ? 00:00:00 [kworker/0:0H]
root 7 2 0 Aug27 ? 00:01:49 [rcu_sched]
root 8 2 0 Aug27 ? 00:00:00 [rcu_bh]
root 9 2 0 Aug27 ? 00:00:00 [migration/0]
root 10 2 0 Aug27 ? 00:00:01 [watchdog/0]
root 11 2 0 Aug27 ? 00:00:01 [watchdog/1]
root 12 2 0 Aug27 ? 00:00:00 [migration/1]
root 13 2 0 Aug27 ? 00:00:01 [ksoftirqd/1]
root 15 2 0 Aug27 ? 00:00:00 [kworker/1:0H]
root 16 2 0 Aug27 ? 00:00:01 [watchdog/2]
root 17 2 0 Aug27 ? 00:00:00 [migration/2]
root 18 2 0 Aug27 ? 00:00:00 [ksoftirqd/2]
root 20 2 0 Aug27 ? 00:00:00 [kworker/2:0H]
root 21 2 0 Aug27 ? 00:00:00 [watchdog/3]
root 22 2 0 Aug27 ? 00:00:00 [migration/3]
root 23 2 0 Aug27 ? 00:00:00 [ksoftirqd/3]
root 25 2 0 Aug27 ? 00:00:00 [kworker/3:0H]
root 26 2 0 Aug27 ? 00:00:00 [kdevtmpfs]
......-f选项用于展示完整格式展示列表-F选项类似-f选项，不过扩展更多详细信息-l长描述方式输出进程信息-y配合-l选项关闭一些标志位
如果明确知道进程编号， 可以到 /proc/{PID} 目录下， 查看到该进程的所有信息。比如 /proc/{PID}/cmdline 描述的进程的启动命令。
