yum（对于 CentOS/RHEL）或 apt-get（对于 Ubuntu/Debian）：，，``bash，# 对于 CentOS/RHEL，sudo yum install sendmail，，# 对于 Ubuntu/Debian，sudo apt-get install sendmail，`，，然后启动并启用 sendmail 服务：，，`bash，sudo systemctl start sendmail，sudo systemctl enable sendmail，``