1、顯示/boot/grub/grub.conf中以至少一個空白字符開頭的行；
[root@localhost ~]# grep "^[[:space:]]\+.*" /boot/grub/grub.conf
2、顯示/etc/rc.d/rc.sysinit文件中以#開頭，后面跟至少一個空白字符，而后又有至少一個非空白字符的行；
[root@localhost ~]# grep "^[#][[:space:]]\+[^[:space:]]" /etc/rc.d/rc.sysinit
3、打出netstat -tan命令執行結果中以‘LISTEN’，后或跟空白字符結尾的行；
[root@localhost ~]# netstat -tan | grep "LISTEN[[:space:]]*$"
4、添加用戶bash, testbash, basher, nologin (此一個用戶的shell為/sbin/nologin)，而后找出當前系統上其用戶名和默認shell相同的用戶的信息；
[root@localhost ~]# useradd bash [root@localhost ~]# useradd testbash [root@localhost ~]# useradd basher [root@localhost ~]# useradd -s /sbin/nologin nologin
[root@localhost ~]# egrep "^([[:alnum:]]).*\1$" /etc/passwd
5、顯示當前系統上root、fedora或user1用戶的默認shell；
[root@localhost ~]# cat /etc/passwd | cut -d: -f1,7 | egrep "\<root\>|\<fedora\>|\<user1\>" root:/bin/bash user1:/bin/bash fedora:/bin/bash
6、找出/etc/rc.d/init.d/functions文件中某單詞后面跟一組小括號的行，形如：hello()；
[root@localhost ~]# egrep "[[:alnum:]]\(\)" /etc/rc.d/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() {
7、使用echo命令輸出一個絕對路徑，使用grep取出其基名；
[root@localhost ~]# echo "/etc/sysconfig/" | egrep -o '[^/]+/?$' | cut -d/ -f 1 sysconfig
擴展：取出其路徑名
[root@localhost ~]# echo "/etc/sysconfig/network" | egrep -o '(/.*/)' /etc/sysconfig/
8、找出ifconfig命令結果中的1-255之間數字；
[root@localhost ~]# ifconfig | egrep "([0-9]{1,2}|1[0-9][0-9]|2[0-4][0-9]|25[0-5])"
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.2.99 netmask 255.255.255.0 broadcast 192.168.2.255
inet6 fe80::20c:29ff:fe59:590b prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:59:59:0b txqueuelen 1000 (Ethernet)
RX packets 12214 bytes 1201175 (1.1 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 6328 bytes 1244024 (1.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
RX packets 88 bytes 7436 (7.2 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 88 bytes 7436 (7.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:f7:9e:82 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
9、挑戰題：寫一個模式，能匹配合理的IP地址；
[root@localhost ~]# ifconfig | egrep -o '([0-9]{1,2}|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.
([0-9]{1,2}|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.
([0-9]{1,2}|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.
([0-9]{1,2}|1[0-9][0-9]|2[0-4][0-9]|25[0-5])'
192.168.2.99
255.255.255.0
192.168.2.255
127.0.0.1
255.0.0.0
192.168.122.1
255.255.255.0
192.168.122.255
10、挑戰題：寫一個模式，能匹配出所有的郵件地址；
新建測試文件
[root@localhost ~]# cat mailtest.txt ab123@qq.com aaavvv222dddd@163.com fdafda22@qq.com.cn aaa_bbb@129.com.hk aaaaaaaaaaaaaa 12312321312312 sfds_fdfdfd 777888777@163.com
匹配模式
[root@localhost ~]# egrep "[[:alnum:]]+_?[[:alnum:]]+@[[:alnum:]]+\.[[:alpha:]]+\.?[[:alpha:]]+?" mailtest.txt ab123@qq.com aaavvv222dddd@163.com fdafda22@qq.com.cn aaa_bbb@129.com.hk 777888777@163.com
11、查找/var目錄下屬主為root，且屬組為mail的所有文件或目錄；
[root@localhost ~]# find /var \( -user root -a -group mail \) -ls 67127265 4 drwxrwxr-x 2 root mail 4096 Jul 5 10:00 /var/spool/mail
12、查找當前系統上沒有屬主或屬組的文件；
[root@localhost ~]# find / \( -nouser -a -nogroup \) -ls find: ‘/proc/34206/task/34206/fd/6’: No such file or directory find: ‘/proc/34206/task/34206/fdinfo/6’: No such file or directory find: ‘/proc/34206/fd/6’: No such file or directory find: ‘/proc/34206/fdinfo/6’: No such file or directory 69216572 0 drwxr-xr-x 2 27 27 6 Nov 21 2015 /var/lib/mysql 137041146 0 drwxr-x--- 2 27 27 24 Mar 11 22:33 /var/log/mariadb 137041147 0 -rw-r----- 1 27 27 0 Mar 11 22:33 /var/log/mariadb/mariadb.log
進一步：查找當前系統上沒有屬主或屬組，且最近3天內曾被訪問過的文件或目錄；
[root@localhost ~]# find / \( -nouser -a -nogroup -a -atime -3 \) -ls find: ‘/proc/34603/task/34603/fd/6’: No such file or directory find: ‘/proc/34603/task/34603/fdinfo/6’: No such file or directory find: ‘/proc/34603/fd/6’: No such file or directory find: ‘/proc/34603/fdinfo/6’: No such file or directory 69216572 0 drwxr-xr-x 2 27 27 6 Nov 21 2015 /var/lib/mysql 137041146 0 drwxr-x--- 2 27 27 24 Mar 11 22:33 /var/log/mariadb
13、查找/etc目錄下所有用戶都有寫權限的文件；
[root@localhost ~]# find /etc -perm -222 -ls
14、查找/etc目錄下大于1M，且類型為普通文件的所有文件；
[root@localhost ~]# find /etc -size +1M -type f -ls 4654340 6852 -r--r--r-- 1 root root 7014922 Mar 11 23:24 /etc/udev/hwdb.bin 134959433 1364 -rw-r--r-- 1 root root 1395438 Nov 22 2015 /etc/gconf/schemas/ekiga.schemas 141310667 1308 -rw------- 1 root root 1338053 Jun 27 21:41 /etc/selinux/targeted/contexts/files/file_contexts.bin 7278517 3712 -rw-r--r-- 1 root root 3799487 Jun 27 21:41 /etc/selinux/targeted/policy/policy.29 205532203 1336 -rw-r--r-- 1 root root 1367395 Mar 6 2015 /etc/brltty/zh-tw.ctb
15、查找/etc/init.d/目錄下，所有用戶都有執行權限，且其它用戶有寫權限的文件；
[root@localhost ~]# find /etc/init.d -perm -113 -ls
16、查找/usr目錄下不屬于root、bin或hadoop的文件；
[root@localhost ~]# find /usr -not \( -user root -o -user bin -o -user hadoop \) -ls 68833034 4 drwx------ 2 polkitd root 4096 Mar 11 22:51 /usr/share/polkit-1/rules.d 2416036 16 -rwsr-sr-x 1 abrt abrt 15336 Dec 1 2015 /usr/libexec/abrt-action-install-debuginfo-to-abrt-cache
17、查找/etc/目錄下至少有一類用戶沒有寫權限的文件；
[root@localhost ~]# find /etc/ -not -perm -222 -ls
18、查找/etc目錄下最近一周內其內容被修改過，且不屬于root或hadoop的文件；
[root@localhost ~]# find /etc/ \( -mtime -7 -a -not -user root -a -not -user hadoop \) -ls
原創文章，作者：Anaconda，如若轉載，請注明出處：http://www.www58058.com/21257
寫的很好，排版也很棒，有的還是可以優化一下的，加油