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guluo 写了：我想知道Ubuntu的默认runlevel是在哪里设置的？我的系统的Ubuntu16.04LTS

guluo 写了：但是启动完成之后，我利用runlevel命令显示的是N 5.[/u]

# ll /sbin/runlevel
lrwxrwxrwx 1 root root 14 Mar 29 03:23 /sbin/runlevel -> /bin/systemctl

guluo 写了：其中rc-sysinit.conf中设置的默认runlevel=2

action_table[_ACTION_MAX] = {
[ACTION_HALT] = { SPECIAL_HALT_TARGET, "halt", "replace-irreversibly" },
[ACTION_POWEROFF] = { SPECIAL_POWEROFF_TARGET, "poweroff", "replace-irreversibly" },
[ACTION_REBOOT] = { SPECIAL_REBOOT_TARGET, "reboot", "replace-irreversibly" },
[ACTION_KEXEC] = { SPECIAL_KEXEC_TARGET, "kexec", "replace-irreversibly" },
[ACTION_RUNLEVEL2] = { SPECIAL_MULTI_USER_TARGET, NULL, "isolate" },
[ACTION_RUNLEVEL3] = { SPECIAL_MULTI_USER_TARGET, NULL, "isolate" },
[ACTION_RUNLEVEL4] = { SPECIAL_MULTI_USER_TARGET, NULL, "isolate" },
[ACTION_RUNLEVEL5] = { SPECIAL_GRAPHICAL_TARGET, NULL, "isolate" },
[ACTION_RESCUE] = { SPECIAL_RESCUE_TARGET, "rescue", "isolate" },
[ACTION_EMERGENCY] = { SPECIAL_EMERGENCY_TARGET, "emergency", "isolate" },
[ACTION_DEFAULT] = { SPECIAL_DEFAULT_TARGET, "default", "isolate" },
[ACTION_EXIT] = { SPECIAL_EXIT_TARGET, "exit", "replace-irreversibly" },
[ACTION_SUSPEND] = { SPECIAL_SUSPEND_TARGET, "suspend", "replace-irreversibly" },
[ACTION_HIBERNATE] = { SPECIAL_HIBERNATE_TARGET, "hibernate", "replace-irreversibly" },
[ACTION_HYBRID_SLEEP] = { SPECIAL_HYBRID_SLEEP_TARGET, "hybrid-sleep", "replace-irreversibly" },
};

vickycq 写了：

guluo 写了：我想知道Ubuntu的默认runlevel是在哪里设置的？我的系统的Ubuntu16.04LTS

Ubuntu 16.04 LTS 使用 systemd 替代 sysvinit，不存在运行级的概念。
快速了解 systemd 常用命令：https://linuxtoy.org/archives/systemd-cheatsheet.html

guluo 写了：但是启动完成之后，我利用runlevel命令显示的是N 5.[/u]

代码： 全选

# ll /sbin/runlevel
lrwxrwxrwx 1 root root 14 Mar 29 03:23 /sbin/runlevel -> /bin/systemctl

在systemd工具集中，runlevel 是 /bin/systemctl的符号链接。 它是向后兼容的垫片，简单来说是调用systemd的主命令行界面：systemctl。

guluo 写了：其中rc-sysinit.conf中设置的默认runlevel=2

如果您希望设置 runlevel=2 以开机默认进入字符界面，可执行命令 systemctl set-default multi-user.target。如果您希望恢复默认进入图形界面，可执行命令 systemctl set-default graphical.target。

systemd 中 target 与传统 runlevel 的对应关系如图

action_table[_ACTION_MAX] = {
[ACTION_HALT] = { SPECIAL_HALT_TARGET, "halt", "replace-irreversibly" },
[ACTION_POWEROFF] = { SPECIAL_POWEROFF_TARGET, "poweroff", "replace-irreversibly" },
[ACTION_REBOOT] = { SPECIAL_REBOOT_TARGET, "reboot", "replace-irreversibly" },
[ACTION_KEXEC] = { SPECIAL_KEXEC_TARGET, "kexec", "replace-irreversibly" },
[ACTION_RUNLEVEL2] = { SPECIAL_MULTI_USER_TARGET, NULL, "isolate" },
[ACTION_RUNLEVEL3] = { SPECIAL_MULTI_USER_TARGET, NULL, "isolate" },
[ACTION_RUNLEVEL4] = { SPECIAL_MULTI_USER_TARGET, NULL, "isolate" },
[ACTION_RUNLEVEL5] = { SPECIAL_GRAPHICAL_TARGET, NULL, "isolate" },
[ACTION_RESCUE] = { SPECIAL_RESCUE_TARGET, "rescue", "isolate" },
[ACTION_EMERGENCY] = { SPECIAL_EMERGENCY_TARGET, "emergency", "isolate" },
[ACTION_DEFAULT] = { SPECIAL_DEFAULT_TARGET, "default", "isolate" },
[ACTION_EXIT] = { SPECIAL_EXIT_TARGET, "exit", "replace-irreversibly" },
[ACTION_SUSPEND] = { SPECIAL_SUSPEND_TARGET, "suspend", "replace-irreversibly" },
[ACTION_HIBERNATE] = { SPECIAL_HIBERNATE_TARGET, "hibernate", "replace-irreversibly" },
[ACTION_HYBRID_SLEEP] = { SPECIAL_HYBRID_SLEEP_TARGET, "hybrid-sleep", "replace-irreversibly" },
};

我想知道Ubuntu的默认runlevel是在哪里设置的？

guluo 写了：那系统再启动的时候是依据什么来选择runlevel*.target文件的？会不会有一个默认的选择文件？

# ll /etc/systemd/system/default.target
lrwxrwxrwx 1 root root 36 Nov 21 16:01 /etc/systemd/system/default.target -> /lib/systemd/system/graphical.target