组合多个系统命令，通过脚本实现修改系统配置
#/bin/bash
# 设置时区并同步时间
ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
if ! crontab -l |grep ntpdate &>/dev/null ; then(echo "* 1 * * * ntpdate time.windows.com >/dev/null 2>&1";crontab -l) |crontab
fi# 禁用selinux
sed -i '/SELINUX/{s/permissive/disabled/}' /etc/selinux/config# 关闭防火墙
if egrep "7.[0-9]" /etc/redhat-release &>/dev/null; thensystemctl stop firewalldsystemctl disable firewalld
elif egrep "6.[0-9]" /etc/redhat-release &>/dev/null; thenservice iptables stopchkconfig iptables off
fi# 历史命令显示操作时间
if ! grep HISTTIMEFORMAT /etc/bashrc; thenecho 'export HISTTIMEFORMAT="%F %T `whoami` "' >> /etc/bashrc
fi# SSH超时时间
if ! grep "TMOUT=600" /etc/profile &>/dev/null; thenecho "export TMOUT=600" >> /etc/profile
fi# 禁止root远程登录
sed -i 's/#PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config# 禁止定时任务向发送邮件
sed -i 's/^MAILTO=root/MAILTO=""/' /etc/crontab# 设置最大打开文件数
if ! grep "* soft nofile 65535" /etc/security/limits.conf &>/dev/null; thencat >> /etc/security/limits.conf << EOF* soft nofile 65535* hard nofile 65535
EOF
fi# 系统内核优化
cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_tw_buckets = 20480
net.ipv4.tcp_max_syn_backlog = 20480
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_fin_timeout = 20
EOF# 减少SWAP使用
echo "0" > /proc/sys/vm/swappiness命令行示例
[root@iZ2vcgxbgi6b6kbx279yozZ test]# ./sys_conf.sh
export HISTTIMEFORMAT="%F %T `whoami` "
[root@iZ2vcgxbgi6b6kbx279yozZ test]#