创建swap分区
1) 开启Linux系统前添加一块大小为15G的SCSI硬盘
2) 开启系统,右击桌面,打开终端
3) 为新加的硬盘分区,一个主分区大小为5G,剩余空间给扩展分区,在扩展分区上划分1个逻辑分区,大小为5G
4) 格式化主分区为ext3系统
~ mkfs.ext3 /dev/sdb1
5) 将逻辑分区设置为交换分区
~ mkswap /dev/sdb5
6) 启用上一步的交换分区
~ swapon /dev/sdb5
7) 查看交换分区的状态
~ swapon -s~ swapoff /dev/sdb5#关闭交换分区swap
free命令查看内存
buffer与cache的作用这二者是为了提高IO性能的,由OS(操作系统)管理
buffer是用于存放要输出到disk(块设备)的数据
cache是存放从disk读出的数据。
#释放被系统cache占用的数据echo 3>/proc/sys/vm/drop_caches
计算真实的内存使用率
参考资料
#对于系统来说,buffers和cache是已经被使用的#free=total-used#对于应用程序来说#free=buffers+cache+free#so#使用率=used/total*100%free-m|sed-n'2p'|awk'{print"usedmemis"$3"M,totalmemis"$2"M,usedpercentis"$3/$2*100"%"}'
dd命令测试硬盘速度
~ dd if=/dev/zero of=a.txt bs=20M count=2
查询firewall进程,然后杀死
~ ps aux | grep firewallroot 857 0.0 2.4 327396 25124 ? Ssl 14:52 0:00 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopidroot5274 0.0 0.0 112668 968 pts/0 S+ 16:01 0:00 grep --color=auto firewall~ kill -9 857
rpm命令
1) 挂载光盘文件到/media目录
~ mount /dev/sr0 /media
2) 进去/media目录下的Packages目录
~ cd /media/Packages
3) 查看系统已安装的所有rpm包
~ rpm -qa
4) 查看系统是否安装dhcp软件包
~ rpm -qa | grep dhcpdhcp-libs-4.2.5-47.el7.centos.x86_64dhcp-common-4.2.5-47.el7.centos.x86_64
5) 安装dhcp软件包
~ ls /media/Packages/ | grep dhcp#查询结果有3个,有两个已经安装,所以安装没有安装的那个dhcp~ rpm -ivh /media/Packages/dhcp-4.2.5-47.el7.centos.x86_64.rpm或~ yum install dhcp
6) 查看dhcp软件包的信息
~ rpm -qi dhcp
7) 查看dhcp软件包中所包含的所有文件
~ ls /media/Packages | dhcp~ rpm -qlp /media/Packages/dhcp-4.2.5-47.el7.centos.x86_64.rpm/etc/NetworkManager/etc/NetworkManager/dispatcher.d/etc/NetworkManager/dispatcher.d/12-dhcpd/etc/dhcp/etc/dhcp/dhcpd.conf/etc/dhcp/dhcpd6.conf/etc/openldap/schema/dhcp.schema/etc/sysconfig/dhcpd/usr/bin/omshell/usr/lib/systemd/system/dhcpd.service/usr/lib/systemd/system/dhcpd6.service/usr/lib/systemd/system/dhcrelay.service/usr/sbin/dhcpd/usr/sbin/dhcrelay/usr/share/doc/dhcp-4.2.5/usr/share/doc/dhcp-4.2.5/dhcpd.conf.example/usr/share/doc/dhcp-4.2.5/dhcpd6.conf.example/usr/share/doc/dhcp-4.2.5/ldap/usr/share/doc/dhcp-4.2.5/ldap/README.ldap/usr/share/doc/dhcp-4.2.5/ldap/dhcp.schema/usr/share/doc/dhcp-4.2.5/ldap/dhcpd-conf-to-ldap/usr/share/man/man1/omshell.1.gz/usr/share/man/man5/dhcpd.conf.5.gz/usr/share/man/man5/dhcpd.leases.5.gz/usr/share/man/man8/dhcpd.8.gz/usr/share/man/man8/dhcrelay.8.gz/usr/share/systemtap/tapset/dhcpd.stp/var/lib/dhcpd/var/lib/dhcpd/dhcpd.leases/var/lib/dhcpd/dhcpd6.leases
或
~ yum install --downloadonly dhcp#只下载不安装~ rpm -qlp /var/cache/yum/x86_64/7/base/packages/dhcp-4.2.5-47.el7.centos.x86_64.rpm #软件并未安装,而且身边也没有安装ISO的情况适用
8) 查看/bin/ls文件是由哪个软件包产生
~ which ls
9) 卸载dhcp软件包
~ rpm -e dhcp
yum命令
1) 自定义yum仓库:createrepo
~ mkdir /httpd_bak~ createrope /httpd_bakSaving Primary metadataSaving file lists metadataSaving other metadataGenerating sqlite DBsSqlite DBs complete
2) 自定义repo文件
~ cd /etc/yum.repos.d/~ mv * /tmp/bak/~ vim httpd.repo
httpd.reop 文件内容
[httpd]# []内容自定义name=httpd server # []内的内容自定义basurl=file:///http_bak# yum的目标文件夹enabled=1#代表开启这个yum源gpgcheck=0 #关闭状态,不检测gpg认证
3) 使用yum命令安装httpd软件包
~ rpm -ivh /media/Packages/httpd-2.4.6-45.el7.centos.x86_64.rpm错误:依赖检测失败:httpd-tools = 2.4.6-45.el7.centos 被 httpd-2.4.6-45.el7.centos.x86_64 需要libapr-1.so.0()(64bit) 被 httpd-2.4.6-45.el7.centos.x86_64 需要libaprutil-1.so.0()(64bit) 被 httpd-2.4.6-45.el7.centos.x86_64 需要~ cp /media/Packages/mailcap-2.1.41-2.el7.noarch.rpm /httpd_bak/~ cp /media/Packages/apr-1.4.8-3.el7.x86_64.rpm /httpd_bak/~ cp /media/Packages/apr-util-1.5.2-6.el7.x86_64.rpm /httpd_bak/~ cp /media/Packages/apr-1.4.8-3.el7.x86_64.rpm /httpd_bak/~ cp /media/Packages/apr-devel-1.4.8-3.el7.x86_64.rpm /httpd_bak/~ cp /media/Packages/httpd-2.4.6-45.el7.centos.x86_64.rpm /httpd_bak/~ yum install httpd -y #或yum -y install httpd
4) 卸载httpd软件包:yum –y remove 软件名
~ yum -y erase httphs #-y 不提示确认
5) 使用yum安装组件'KDE 桌面':yum –y groupinstall 组件名
~ yum groupinstall 'KDE Plasma Workspaces'
6) 掌握使用yum删除组件‘KDE 桌面’:yum –y groupremove 组件名
~ yum grouplist #先查看组件~ yum groupmove 'KDE Plasma Workspaces'
7) 掌握清除yum缓存:yum clean all
~ yum clean all# yum makecache -y 创建缓存
8) 使用yum查找软件包:yum search 软件包名
~ yum search httpd
源码安装python
~ wget /ftp/python/3.6.0/Python-3.6.0.tgz~ yum grouplist #查看组件~ yum groupinstall '开发工具' #安装'开发工具'组件~ yum install zlib* -y~ tar xvf Python-3.6.0.tgz # 解压python压缩包~ cd Python-3.6.0 #切换目录~ ./configure --prefix=/usr/local/python3.6 #编译并指定安装目录~ make && make install~ ln -s /usr/local/python3.6/bin/ /sbin/#建立软链接