################################编译系统内核###################################

进入内核编辑区域

cd /usr/src

多线程支持加快编译速度（注意：cpu的占用率会升高）

make -j4 buildworld

备份原有内核

cd /usr/src/sys/i386/conf

cp GENERIC  /root/GENERIC.OLD

编辑内核

ee NS1

建立内核

cd /usr/src

make buildkernel

安装内核

make installkernel

重新启动计算机

shutdown -r now

mergemaster -p

更新系统配置文件。这个命令后会跟随多个提示问题建议仔细阅读后做出选择，如果是安装系统后第一次同步代码，并是在没有安装任何软件的情况下，可以考虑执行mergemaster –ai

“跳过询问信息选择全部更新”

提示如下：

www# mergemaster -p

*** Creating the temporary root environment in /var/tmp/temproot

 *** /var/tmp/temproot ready for use

 *** Creating and populating directory structure in /var/tmp/temproot

*** Beginning comparison

 *** Temp ./etc/master.passwd and installed have the same CVS Id, deleting

 *** Temp ./etc/group and installed have the same CVS Id, deleting

*** Comparison complete

Do you wish to delete what is left of /var/tmp/temproot? [no] yes

//我选择了yes删除/var/tmp/temproot

//将会有以下显示结果

*** /var/tmp/temproot has been deleted

grep: /etc/make.conf: No such file or directory

*** Comparing make variables

*** From /etc/make.conf

*** From /usr/src/share/examples/etc/make.conf

更新系统配置文件

cd /usr/src

make installworld

mergemaster

shutdown -r now

删除/usr/obj（以防影响下一次编译内核）

cd /usr/obj

chflags -R noschg *

rm -rf *