1、通过ps命令的两种选项形式查看进程信息
[root@localhost ~]# ps aux
[root@localhost ~]# ps -elf
2、通过top命令查看进程
[root@localhost ~]# top
3、通过pgrep命令查看sshd服务的进程号
[root@localhost ~]# pgrep -l sshd
1166 sshd
13754 sshd
4、查看系统进程树
[root@localhost ~]# pstree -a
5、使dd if=/dev/zero of=/root/file bs=1M count=8190 命令操作在前台运行
[root@localhost ~]# dd if=/dev/zero of=/root/file bs=1M count=8190
6、将第5题命令操作调入到后台并暂停
^Z
[1]+  已停止               dd if=/dev/zero of=/root/file bs=1M count=8190
[root@localhost ~]# jobs 1
[1]+  已停止               dd if=/dev/zero of=/root/file bs=1M count=8190

7、使dd if=/dev/zero of=/root/file2 bs=1M count=1024 命令操作在后台运行
[root@localhost ~]# dd if=/dev/zero of=/root/file2 bs=1M count=1024 &
[2] 54226
8、查看后台的任务列表
[root@localhost ~]# jobs 2
[2]-  运行中               dd if=/dev/zero of=/root/file2 bs=1M count=1024 &
9、恢复dd if=/dev/zero of=/root/file bs=1M count=8190 让其在后台继续运行
[root@localhost ~]# bg 1
[root@localhost ~]# jobs 1
[1]+  运行中               dd if=/dev/zero of=/root/file bs=1M count=8190 &
10、查询dd if=/dev/zero of=/root/file bs=1M count=8190 命令的进程并通过kill杀死
[root@localhost ~]# pgrep -l "dd"
2 kthreadd
41 ipv6_addrconf
13354 evolution-addre
13380 evolution-addre
15780 dd
[root@localhost ~]# kill -9 15780
[root@localhost ~]# jobs 1
[1]+  已杀死               dd if=/dev/zero of=/root/file bs=1M count=8190
11、设置一次性计划任务在18：00时关闭系统，并查看任务信息
[root@localhost ~]# at 18:00
at> init 0
at> <EOT>
job 2 at Thu Aug  8 18:00:00 2019
[root@localhost ~]# atq
2 Thu Aug  8 18:00:00 2019 a root
12、以root身份设置周期性计划任务
a) 每天晚上的24点时打包压缩 /etc/passwd /etc/shadow /etc/group /etc/gshadow 为 file.tar.gz
[root@localhost ~]# crontab -e
0       0       *       *       *       /usr/bin/tar cfz file.tar.gz /etc/passwd /etc/shadow /etc/group /etc/gshadow
b) 每周一的每隔五分钟列出磁盘使用状况
*/5     *       *       *       1       du -as
c) 每天的8:30与互联网时间同步服务器pool.ntp.org同步时间
30      8       *       *       *       ntpdate pool.ntp.org
13、通过crontab命令查看root的计划任务，通过文件查看类工具列出/var/spool/cron下对应的文件内容
[root@localhost ~]# crontab -l
0 0 * * * /usr/bin/tar cfz file.tar.gz /etc/passwd /etc/shadow /etc/group /etc/gshadow
*/5 * * * 1 du -as
30 8 * * * ntpdate pool.ntp.org
[root@localhost ~]# ls /var/spool/cron/
root
[root@localhost ~]# vim /var/spool/cron/root
0       0       *       *       *       /usr/bin/tar cfz file.tar.gz /etc/passwd /etc/shadow /etc/group /etc/gshadow
*/5     *       *       *       1       du -as
30      8       *       *       *       ntpdate pool.ntp.org
~                                                                                 
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"/var/spool/cron/root" 3L, 138C 已写入