systemctl 命令详解及使用教程( 四 ) _systemctl

29.获取服务的依赖项列表（httpd）
# systemctl list-dependencies httpd.servicehttpd.service├─system.slice└─basic.target├─firewalld.service├─microcode.service├─rhel-autorelabel-mark.service├─rhel-autorelabel.service├─rhel-configure.service├─rhel-dmesg.service├─rhel-loadmodules.service├─paths.target├─slices.target│ ├─-.slice│ └─system.slice├─sockets.target│ ├─dbus.socket....30.按层次列出控制组
# systemd-cgls├─1 /usr/lib/systemd/systemd --switched-root --system --deserialize 23├─user.slice│ └─user-0.slice│└─session-1.scope│├─2498 sshd: root@pts/0│├─2500 -bash│├─4521 systemd-cgls│└─4522 systemd-cgls└─system.slice├─httpd.service│ ├─4440 /usr/sbin/httpd -DFOREGROUND│ ├─4442 /usr/sbin/httpd -DFOREGROUND│ ├─4443 /usr/sbin/httpd -DFOREGROUND│ ├─4444 /usr/sbin/httpd -DFOREGROUND│ ├─4445 /usr/sbin/httpd -DFOREGROUND│ └─4446 /usr/sbin/httpd -DFOREGROUND├─polkit.service│ └─721 /usr/lib/polkit-1/polkitd --no-debug....31.根据CPU ，内存，输入和输出列出控制组
# systemd-cgtopPathTasks%CPUMemoryInput/s Output/s/831.0437.8M--/system.slice-0.1---/system.slice/mariadb.service20.1---/system.slice/tuned.service10.0---/system.slice/httpd.service60.0---/system.slice/NetworkManager.service1----/system.slice/atop.service1----/system.slice/atopacct.service1----/system.slice/auditd.service1----/system.slice/crond.service1----/system.slice/dbus.service1----/system.slice/firewalld.service1----/system.slice/lvm2-lvmetad.service1----/system.slice/polkit.service1----/system.slice/postfix.service3----/system.slice/rsyslog.service1----/system.slice/system-getty.slice/getty@tty1.service1----/system.slice/systemd-journald.service1----/system.slice/systemd-logind.service1----/system.slice/systemd-udevd.service1----/system.slice/webmin.service1----/user.slice/user-0.slice/session-1.scope3----控制系统运行级别32.如何启动系统救援模式
# systemctl rescueBroadcast message from root@tecmint on pts/0 (Wed 2015-04-29 11:31:18 IST):The system is going down to rescue mode NOW!33.如何进入紧急模式。
# systemctl emergencyWelcome to emergency mode! After logging in, type "journalctl -xb" to viewsystem logs, "systemctl reboot" to reboot, "systemctl default" to try againto boot into default mode.34.列出当前使用的运行级别
# systemctl get-defaultmulti-user.target5.如何启动Runlevel 5 aka图形模式。
# systemctl isolate runlevel5.targetOR# systemctl isolate graphical.target36.如何启动Runlevel 3又称多用户模式（命令行）
# systemctl isolate runlevel3.targetOR# systemctl isolate multiuser.target36.如何将多用户模式或图形模式设置为默认运行级别
# systemctl set-default runlevel3.target# systemctl set-default runlevel5.target37.如何重启，暂停，暂停，休眠或将系统置于混合睡眠状态
# systemctl reboot# systemctl halt# systemctl suspend# systemctl hibernate# systemctl hybrid-sleep对于那些可能不了解跑步水平及其作用的人。