初始centOS系统环境

#!/bin/bash
#
# 1. 在线安装一些编译环境
# 2. 关闭防火墙
# 3. 修改内核参数#
#
yuminst(){ 
  #update yum  
  yum -y update 
  #install epel EPEL 是yum的一个软件源，里面包含了许多基本源里没有的软件 
  wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm 
  wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm 
  sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm 
  #install  
  yum install -y setuptool ntsysv iptables pcre-devel openssl-devel bzip2-devel xinetd lrzsz lsof system-config-securitylevel-tui system-config-network-tui apr-util xorg-x11-drv-penmount perl-DBD-MySQL bind-utils --nogpgcheck 
  yum install -y zip unzip --nogpgcheck 
  yum install -y libselinux-python python-devel 
  yum install -y net-snmp #net-snmp-perl net-snmp-utils net-snmp-devel 
  yum install -y mlocate --nogpgcheck 
  updatedb 
  yum install -y ncurses ncurses-devel bison 
  yum install -y glibc glibc-common glibc-devel gd gd-devel libtool libpcap libpcap-devel gdbm gdbm-devel zlib zlib-devel libxslt audit-libs-devel --nogpgcheck 
  yum install -y openssh openssh-server openssh-clients --nogpgcheck 
  yum install -y make cmake vim* gcc gcc-c++ --nogpgcheck 
  yum install -y nfs-utils nfs-utils-lib nfs4-acl-tools cifs-utils xfsprogs --nogpgcheck 
  yum install -y crontabs vixie-cron --nogpgcheck                
  yum install -y ntp --nogpgcheck 
  yum install -y telnet
  #yum -y install wget
}

ser(){ 
  /etc/init.d/crond start 
  chkconfig crond on 
  /etc/init.d/iptables stop 
  chkconfig iptables off 
  /etc/init.d/sshd start 
  chkconfig sshd on 
  setenforce 0 
  sed -ri 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
}

kernal(){ 
  #内核参数修改 
  modprobe nf_conntrack 
  echo "modprobe nf_conntrack" >> /etc/rc.local 
  modprobe bridge 
  echo "modprobe bridge" >> /etc/rc.local 
  echo ' 
  net.ipv4.tcp_fin_timeout = 60 
  net.ipv4.tcp_tw_reuse = 1 
  net.ipv4.tcp_tw_recycle = 1 
  net.ipv4.tcp_syncookies = 1 
  net.ipv4.tcp_max_syn_backlog = 16384 
  net.ipv4.tcp_max_tw_buckets = 36000 
  net.ipv4.route.gc_timeout = 100 
  net.ipv4.tcp_syn_retries = 2 
  net.ipv4.tcp_synack_retries = 1 
  net.core.somaxconn = 32768 
  net.core.netdev_max_backlog = 32768 
  net.ipv4.tcp_max_orphans = 327680 

  net.nf_conntrack_max = 102400 
  net.netfilter.nf_conntrack_max = 102400    
  net.netfilter.nf_conntrack_tcp_timeout_established = 180 
  net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120 
  net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60 
  net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120' >> /etc/sysctl.conf    

  sysctl -p 
  echo ''
}

filelimit(){ 
    #修改打开文件限制  
    echo 'ulimit -n 65535' >> /etc/profile 
    source /etc/profile 
    echo '*       soft nproc 65535 
    *       hard nproc 65535 
    *       soft nofile 65535 
    *       hard nofile 65535' >> /etc/security/limits.conf 
    echo '* soft nproc 65535' >> /etc/security/limits.d/90-nproc.conf 
    echo -e "================= 修改打开文件限制完成 ================="
}

 echo "1: yum安装基础环境"
 echo "2: 修改内核参数及文件限制"
 echo "3: all"
 read -p "请选择：" num
 if [ -z $num ];then 
    echo $num
 elif [ $num -eq 1 ];then 
    yuminst ser
 elif [ $num -eq 2 ];then 
    kernal 
    filelimit
 elif [ $num -eq 3 ];then 
    yuminst 
    ser 
    kernal filelimit
 else 
    echo "请输入正确选项" 
    exit
fi