RHCE7 管理II-2 通过grep使用正则表达式

grep

-i：忽略大小写

-n：表示行数

找出含有root的行

# grep root /etc/passwd
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

找出以root为首的行,需要添加特殊字符"^"

# grep ^root /etc/passwd
root:x:0:0:root:/root:/bin/bash

找出以"/sbin/nologin"结尾的行，需要添加特殊字符"$"

# grep /sbin/nologin$ /etc/passwd
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin

找出没有出现root的行

# grep -v root /etc/passwd
vboxadd:x:992:1::/var/run/vboxadd:/bin/false
dhcpd:x:177:177:DHCP server:/:/sbin/nologin

找出既没有root，也没有nologin的行

# grep -v root /etc/passwd|grep -v nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
yb:x:1000:1000:yb:/home/yb:/bin/bash
vboxadd:x:992:1::/var/run/vboxadd:/bin/false

# grep -E -v root|nologin /etc/passwd
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
yb:x:1000:1000:yb:/home/yb:/bin/bash
vboxadd:x:992:1::/var/run/vboxadd:/bin/false

grep和rpm结合使用示例

找出文件network-scripts属于哪个安装包
# rpm -qf /etc/sysconfig/network-scripts/
initscripts-9.49.17-1.el7.x86_64

找出initscripts-9.49.17-1.el7.x86_64包的帮助文档在哪里
[root@server initscripts-9.49.17]# rpm -qd initscripts-9.49.17-1.el7.x86_64
/usr/share/doc/initscripts-9.49.17/COPYING
/usr/share/doc/initscripts-9.49.17/changes.ipv6
/usr/share/doc/initscripts-9.49.17/ipv6-6to4.howto
/usr/share/doc/initscripts-9.49.17/ipv6-tunnel.howto
/usr/share/doc/initscripts-9.49.17/static-routes-ipv6
/usr/share/doc/initscripts-9.49.17/sysconfig.txt
/usr/share/doc/initscripts-9.49.17/sysvinitfiles
/usr/share/man/man1/consoletype.1.gz
/usr/share/man/man1/genhostid.1.gz
/usr/share/man/man1/ipcalc.1.gz
/usr/share/man/man1/netreport.1.gz
/usr/share/man/man1/usleep.1.gz
/usr/share/man/man8/ifdown.8.gz
/usr/share/man/man8/ifup.8.gz
/usr/share/man/man8/ppp-watch.8.gz
/usr/share/man/man8/service.8.gz
/usr/share/man/man8/sushell.8.gz
/usr/share/man/man8/sys-unconfig.8.gz
/usr/share/man/man8/usernetctl.8.gz

进入帮助文档所在目录，查看配置ip文档
# cd /usr/share/doc/initscripts-9.49.17
# grep -ri 'IPADDR' *              --这里的*表示所有文件，r表示递归，i表示忽略大小写
ipv6-6to4.howto:IPADDR=xx.yy.zz.ww           [Globally unique IPv4 address]
ipv6-6to4.howto:address (IPADDR= above), here '193.94.160.1'.
sysconfig.txt:  bother to define; you can figure out what "IPADDR" is, I
sysconfig.txt:    IPADDRn=
sysconfig.txt:    LOCAL_IP=     will be converted to IPADDR by netconf
sysconfig.txt:    MY_INNER_IPADDR=local IP address of the tunnel interface
sysconfig.txt:    PEER_OUTER_IPADDR=IP address of the remote tunnel endpoint
sysconfig.txt:    MY_OUTER_IPADDR=IP address of the local tunnel endpoint
sysconfig.txt:    PEER_INNER_IPADDR=IP address of the remote end of the tunnel interface
sysconfig.txt:      If this is specified, a route to PEER_INNER_IPADDR through the tunnel
# more sysconfig.txt