由于手动修改 hosts 文件来实现 github 的访问比较麻烦，为此特意写了两个脚本（针对 linux 平台 和 windows 平台）来实现自动修改 github hosts 。

修改 hosts 的整体流程如下：

• 下载 hosts
• 备份系统原 hosts
• 利用下载的 hosts 来更新系统 hosts

Linux 平台

• 创建名为 github-hosts.sh 的 bash 脚本文件：

  touch github-hosts.sh
  

• 赋予该脚本可执行权限：

  chmod +x github-hosts.sh
  

• 向脚本写入如下内容：

  #!/bin/bash
  
  download_hosts_path=~/hosts   # hosts 下载路径
  hosts_path=/etc/hosts         # 系统 hosts 保存路径
  hosts_path_bak=/etc/hosts.bak # 系统 hosts 备份路径
  
  # 下载 hosts
  echo "########## downloading hosts about github to $download_hosts_path ##########"
  wget -O $download_hosts_path https://gitee.com/ineo6/hosts/raw/master/hosts
  
  # 备份 hosts
  echo "########## copying $hosts_path to $hosts_path_bak ##########"
  sudo cp $hosts_path $hosts_path_bak
  
  # 删除 hosts 中原有 github 相关配置
  echo "########## removing hosts about github in $hosts_path ##########"
  sudo sed -i ":begin; /# GitHub Host Start/,/# GitHub Host End/ { /# GitHub Host End/! { $! { N; b begin }; }; s/# GitHub Host Start.*# GitHub Host End//; };" $hosts_path
  sudo sh -c "sed -i '/^$/d' $hosts_path" # 删除系统 hosts 文件中的空行
  
  # 更新 hosts
  echo "########## updating hosts about github in $hosts_path ##########"
  sudo sh -c "sed -i '/^\\s*#.*$/d' $download_hosts_path" # 删除下载 hosts 文件中的注释
  sudo sh -c "sed -i '/^$/d' $download_hosts_path" # 删除下载 hosts 文件中的空行
  host_value=`cat $download_hosts_path` # 读取下载 hosts 文件内容
  host_value=`echo -e "\n# GitHub Host Start\n${host_value}\n# GitHub Host End"`
  sudo sh -c "echo \"$host_value\" >> $hosts_path" # 将新的 hosts 内容追加到系统 hosts 文件中
  

• 执行该脚本：

  bash github-hosts.sh
  

Windows 平台

• 创建名为 github-hosts.ps1 的 powershell 脚本文件

• 向该文件写入如下内容：

  $dowload_url = "https://gitee.com/ineo6/hosts/raw/master/hosts" # 下载地址
  $download_hosts_path = "$HOME\hosts"                            # hosts 下载路径
  $hosts_path = "C:\windows\system32\drivers\etc\hosts"           # 系统 hosts 保存路径
  $hosts_path_bak = "C:\windows\system32\drivers\etc\hosts.bak"   # 系统 hosts 备份路径
  $command = $MyInvocation.MyCommand.Definition                   # powershell 脚本路径
  
  # 判断用户是否为管理员
  function is_admin
  {
      $user = [Security.Principal.WindowsIdentity]::GetCurrent()
      return (New-Object Security.Principal.WindowsPrincipal $user).IsInRole([Security.Principal.WindowsBuiltinRole]::Administrator)
  }
  
  # 下载 hosts
  function download_hosts 
  {
      Write-Host "########## downloading github hosts to $download_hosts_path ##########"
      $client = new-object System.Net.WebClient
      $client.DownloadFile($dowload_url, $download_hosts_path) 
  }
  
  # 备份 hosts
  function backups_hosts 
  {
      Write-Host "########## copying $hosts_path to $hosts_path_bak ##########"
      $original_hosts = Get-Content $hosts_path -Raw
      Set-Content $hosts_path_bak $original_hosts
  }
  
  # 删除 hosts 中原有 github 相关配置
  function remove_hosts 
  {
      Write-Host "########## removing github hosts in $hosts_path ##########"
      $original_hosts = Get-Content $hosts_path -Raw
      $original_hosts = $original_hosts -replace "# GitHub Host Start[\s\S]*?# GitHub Host End", ""
      $original_hosts = ($original_hosts -replace "(?m)^\s*`r`n", "").trim()
      Set-Content $hosts_path $original_hosts
  }
  
  # 更新 hosts
  function update_hosts 
  {
      Write-Host "########## updating github hosts in $hosts_path ##########"
      $new_hosts = Get-Content $download_hosts_path -Raw
      $new_hosts = $new_hosts -replace "#.*", ""
      $new_hosts = ($new_hosts -replace "(?m)^\s*`r`n", "").trim()
      $new_hosts = "", "# GitHub Host Start", $new_hosts, "# GitHub Host End" -join "`n"
      Add-Content $hosts_path $new_hosts
  }
  
  # 刷新 DNS
  function flush_dns 
  {
      Write-Host "########## refreshing DNS ##########"
      ipconfig /flushdns
  }
  
  $is_admin = is_admin
  
  # 非管理员则利用 Start-Process 命令来获取管理员权限
  if (!$is_admin) 
  {
      if ([int](Get-CimInstance -Class Win32_OperatingSystem | Select-Object -ExpandProperty BuildNumber) -ge 6000) {
          Start-Process -FilePath PowerShell.exe -Verb RunAs -ArgumentList $command
          exit
      }
  }
  
  download_hosts
  backups_hosts
  remove_hosts
  update_hosts
  flush_dns
  

• 执行该脚本：

  .\github-hosts.ps1
  

最后

上述两个脚本文件已上传至 https://gitee.com/zhaoyangkun/github-hosts-shell，有需要的朋友可以自行下载。

在这里要特别感谢 ineo6 大佬提供的最新的 github hosts。