1、找出ifconfig命令结果中本机的所有ipv4地址
[root@centos7 ~]# ifconfig |grep -E -o '(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])'
192.168.226.133
255.255.255.0
192.168.226.255
10.1.249.40
255.255.0.0
10.1.255.255
127.0.0.1
255.0.0.0
192.168.122.1
255.255.255.0
192.168.122.255
[root@centos7 ~]#
[root@centos7 ~]# ifconfig | grep -o -E '\<([0-9]|[1-9][0-9]|2[0-4][0-9]|25[0-5])\>\.\<([0-9]|[1-9][0-9]|2[0-4][0-9]|25[0-5])\>\.\<([0-9]|[1-9][0-9]|2[0-4][0-9]|25[0-5])\>\.\<([0-9]|[1-9][0-9]|2[0-4][0-9]|25[0-5])\>'
255.255.255.0
10.1.249.40
255.255.0.0
10.1.255.255
255.0.0.0
255.255.255.0
[root@centos7 ~]# ifconfig|egrep -o '(\<([0-9]|[1-9][0-9]|2[0-4][0-9]|25[0-5])\>\.){3}\<([0-9]|[1-9][0-9]|2[0-4][0-9]|25[0-5])\>'
255.255.255.0
10.1.249.40
255.255.0.0
10.1.255.255
255.0.0.0
255.255.255.0
[root@centos7 ~]#
2、查出分区空间最大的使用率百分比
root@centos7 ~]# df|tail -7|tr -s ' ' ':' /dev/sda3:123157756:3851192:119306564:4%:/ devtmpfs:486124:0:486124:0%:/dev tmpfs:500664:12:500652:1%:/dev/shm tmpfs:500664:26036:474628:6%:/run tmpfs:500664:0:500664:0%:/sys/fs/cgroup /dev/sda1:508588:157108:351480:31%:/boot tmpfs:100136:0:100136:0%:/run/user/0 [root@centos7 ~]# df|tail -7|tr -s ' ' ':'|cut -d: -f5 4% 0% 1% 6% 0% 31% 0% [root@centos7 ~]# df|tail -7|tr -s ' ' ':'|cut -d: -f5 |sort -rn |head -1 31% [root@centos7 ~]#
3、查出用户UID最大值的用户名、UID及shell类型
[root@centos7 ~]# cat /etc/passwd|sort -t: -k3 -nr |head -1|cut -d: -f1,3,7 nfsnobody:65534:/sbin/nologin [root@centos7 ~]#
4、查出/tmp的权限，以数字方式显示
[root@centos7 ~]# stat /tmp|head -4|tail -1 |tr -d '[:punct:][:alpha:]'|tr -s ' ' ":" :1777:0:0: [root@centos7 ~]# stat /tmp|head -4|tail -1 |tr -d '[:punct:][:alpha:]'|tr -s ' ' ":"|cut -d: -f2 1777 [root@centos7 ~]#
5、统计当前连接本机的每个远程主机IP的连接数，并按从大到小排序
[root@centos7 ~]# netstat -tn|grep tcp |tr -s ' ' ':' |cut -d: -f4|uniq -c 4 192.168.226.133 [root@centos7 ~]#
6、显示/proc/meminfo文件中以大小s开头的行；(要求：使 用两种方式)
[root@centos7 ~]# grep "^[sS].*" /proc/meminfo SwapCached: 4 kB SwapTotal: 2098172 kB SwapFree: 2098168 kB Shmem: 26060 kB Slab: 118472 kB SReclaimable: 68372 kB SUnreclaim: 50100 kB [root@centos7 ~]# [root@centos7 ~]# grep -i "^s.*" /proc/meminfo SwapCached: 4 kB SwapTotal: 2098172 kB SwapFree: 2098168 kB Shmem: 26060 kB Slab: 118472 kB SReclaimable: 68372 kB SUnreclaim: 50100 kB [root@centos7 ~]#
7、显示/etc/passwd文件中不以/bin/bash结尾的行
[root@centos7 ~]# grep -v "/bin/bash$" /etc/passwd
8、显示用户rpc默认的shell程序
[root@centos7 ~]# grep "^rpc\>" /etc/passwd |cut -d: -f7 /sbin/nologin [root@centos7 ~]#
9、找出/etc/passwd中的两位或三位数
[root@centos7 ~]# grep -E "\<[1-9][0-9]\>|\<[1-9][0-9][0-9]\>" /etc/passwd
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-bus-proxy:x:999:998:systemd Bus Proxy:/:/sbin/nologin
[root@centos7 ~]# grep "\<[1-9][0-9]\{1,2\}\>" /etc/passwd
[root@centos7 ~]# grep -w "[1-9][0-9][0-9]\?" /etc/passwd
10、显示/etc/grub2.cfg文件中，至少以一个空白字符开头的 且后面存非空白字符的行
grep "^[[:space:]]\+[^[:space:]].*" /etc/grub2.cfg
11、找出"netstat -tan"命令的结果中以'LISTEN'后跟多个空白字符的行
[root@centos7 ~]# netstat -tan |grep "LISTEN[[:space:]]\+" tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp6 0 0 :::22 :::* LISTEN tcp6 0 0 ::1:631 :::* LISTEN tcp6 0 0 ::1:25 :::* LISTEN [root@centos7 ~]#
12、添加用户bash、testbash、basher以及nologin(其shell为 /sbin/nologin),而后找出/etc/passwd文件中用户名同shell名 的行
root@centos7 ~]# grep "^\<\(.*\)\>.*\<\1\>$" /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 bash:x:1007:1007::/home/bash:/bin/bash nologin:x:1009:1009::/home/nologin:/sbin/nologin [root@centos7 ~]# grep "^\<\(.*\)\>.*/\1$" /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 bash:x:1007:1007::/home/bash:/bin/bash nologin:x:1009:1009::/home/nologin:/sbin/nologin [root@centos7 ~]#
13、显示当前系统root、mage或wang用户的UID和默认shell
root@centos7 ~]# grep -E "^\<root\>|^\<mage\>|^\<wang\>" /etc/passwd root:x:0:0:root:/root:/bin/bash wang:x:1003:10011::/home/wang:/bin/bash mage:x:1010:1010::/home/mage:/bin/bash [root@centos7 ~]# grep -E "^\<root\>|^\<mage\>|^\<wang\>" /etc/passwd |cut -d: -f3,7 0:/bin/bash 1003:/bin/bash 1010:/bin/bash [root@centos7 ~]# [root@centos7 ~]# grep -E '^(mage|wang|root)\>' /etc/passwd root:x:0:0:root:/root:/bin/bash wang:x:1003:10011::/home/wang:/bin/bash mage:x:1010:1010::/home/mage:/bin/bash [root@centos7 ~]# grep -E '^(mage|wang|root)\>' /etc/passwd |cut -d: -f3,7 0:/bin/bash 1003:/bin/bash 1010:/bin/bash [root@centos7 ~]#
14、找出/etc/rc.d/init.d/functions文件中行首为某单词(包 括下划线)后面跟一个小括号的行
[root@centos7 ~]# grep -E '^[[:alpha:]_]+\(\)' /etc/init.d/functions
checkpid() {
__pids_var_run() {
__pids_pidof() {
daemon() {
killproc() {
pidfileofproc() {
pidofproc() {
status() {
echo_success() {
echo_failure() {
echo_passed() {
echo_warning() {
update_boot_stage() {
success() {
failure() {
passed() {
warning() {
action() {
strstr() {
is_ignored_file() {
is_true() {
is_false() {
apply_sysctl() {
[root@centos7 ~]#
15、使用egrep取出/etc/rc.d/init.d/functions中其基名
[root@centos7 ~]# echo "/etc/init.d/functions/" |grep -o -E "[^/]+/?$" functions/ [root@centos7 ~]# echo "/etc/sysconfig/"|grep -E -o "[^/]+/?$" sysconfig/ [root@centos7 ~]#
未完结，待续，正则正忙,小编去喝茶了^_^。。。。。:)
本章节总结在如下博客地址欢迎访问：http://purify.blog.51cto.com/
原创文章，作者：alren，如若转载，请注明出处：http://www.178linux.com/29751
