Add systemd

Author: taotieren

README.md

@@ -133,6 +133,32 @@ hosts 文件在每个系统的位置不一，详情如下：
 
 ### 2.3 一行命令 (适用于类 Unix 系统)
 
+#### 使用 Systemd 管理的 Linux
+
+<details>
+<summary><b>Linux 发行版中 systemd 软件包状态</b></summary>
+
+[![Packaging status](https://repology.org/badge/vertical-allrepos/systemd.svg)](https://repology.org/project/systemd/versions)
+
+</details>
+
+```bash
+cd GitHub520
+sudo install -Dm0644 *-github520-hosts* -t /usr/lib/systemd/system/
+sudo systemctl enable --now update-github520-hosts.timer
+sudo systemctl start update-github520-hosts.service
+sudo systemctl status update-github520-hosts.service
+cat /etc/hosts
+sudo systemctl start remove-github520-hosts.service
+cat /etc/hosts
+```
+
+- Arch Linux: [AUR github520-git](https://aur.archlinux.org/packages/github520-git)
+
+```bash
+yay -Syu github520
+```
+
 #### GNU（Ubuntu/CentOS/Fedora）
 
 `sudo sh -c 'sed -i "/# GitHub520 Host Start/Q" /etc/hosts && curl https://raw.hellogithub.com/hosts >> /etc/hosts'`

remove-github520-hosts.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Remove GitHub520 Hosts File
+After=network.target
+
+[Service]
+User=root
+PermissionsStartOnly=true
+ExecStart=/bin/bash -c 'sed -i "/# GitHub520 Host Start/,/# GitHub520 Host End/d" /etc/hosts'
+
+[Install]
+WantedBy=default.target

update-github520-hosts.service

@@ -0,0 +1,14 @@
+[Unit]
+Description=Update GitHub520 Hosts File
+After=network.target
+
+[Service]
+User=root
+PermissionsStartOnly=true
+ExecStart=/bin/bash -c 'sed -i "/# GitHub520 Host Start/Q" /etc/hosts && { wget -O - https://raw.hellogithub.com/hosts || wget -O - https://raw.githubusercontent.com/521xueweihan/GitHub520/main/hosts; } >> /etc/hosts'
+Restart=on-failure
+RestartSec=30
+StartLimitInterval=3min
+
+[Install]
+WantedBy=default.target

update-github520-hosts.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=Update GitHub520 Hosts File Timer
+
+[Timer]
+OnCalendar=*-*-* *:0/1:00
+Persistent=true
+
+[Install]
+WantedBy=timers.target