小白学Linux之正则表达式

1、复制/etc/skel目录为/home/tuser1,要求/home/tuser1及其内部文件的属组和其它用户均没有任何访问权限。

[root@steven /]# cp -rv /etc/skel /home/tuser1

‘/etc/skel’ -> ‘/home/tuser1’

‘/etc/skel/.mozilla’ -> ‘/home/tuser1/.mozilla’

‘/etc/skel/.mozilla/extensions’ -> ‘/home/tuser1/.mozilla/extensions’

‘/etc/skel/.mozilla/plugins’ -> ‘/home/tuser1/.mozilla/plugins’

‘/etc/skel/.bash_logout’ -> ‘/home/tuser1/.bash_logout’

‘/etc/skel/.bash_profile’ -> ‘/home/tuser1/.bash_profile’

‘/etc/skel/.bashrc’ -> ‘/home/tuser1/.bashrc’

[root@steven /]# chmod -R 700 /home/tuser1

[root@steven /]# ll -a /home/tuser1

total 12

drwx——. 3 root root 78 Sep 10 09:00 .

drwxr-xr-x. 6 root root 54 Sep 10 09:00 ..

-rwx——. 1 root root 18 Sep 10 09:00 .bash_logout

-rwx——. 1 root root 193 Sep 10 09:00 .bash_profile

-rwx——. 1 root root 231 Sep 10 09:00 .bashrc

drwx——. 4 root root 39 Sep 10 09:00 .mozilla

2、编辑/etc/group文件,添加组hadoop。

[root@steven /]# vim /etc/group

[root@steven /]# tail -l /etc/group

hadoop:x:5004

 

3、手动编辑/etc/passwd文件新增一行,添加用户hadoop,其基本组ID为hadoop组的id号;其家目录为/home/hadoop。

[root@steven /]# vim /etc/passwd

[root@steven /]# tail -l /etc/passwd

hadoop:x:2003:5004::/home/hadoop:/bin/bash

4、复制/etc/skel目录为/home/hadoop,要求修改hadoop目录的属组和其它用户没有任何访问权限。

[root@steven /]# cp -rv /etc/skel/ /home/hadoop

‘/etc/skel/’ -> ‘/home/hadoop’

‘/etc/skel/.mozilla’ -> ‘/home/hadoop/.mozilla’

‘/etc/skel/.mozilla/extensions’ -> ‘/home/hadoop/.mozilla/extensions’

‘/etc/skel/.mozilla/plugins’ -> ‘/home/hadoop/.mozilla/plugins’

‘/etc/skel/.bash_logout’ -> ‘/home/hadoop/.bash_logout’

‘/etc/skel/.bash_profile’ -> ‘/home/hadoop/.bash_profile’

‘/etc/skel/.bashrc’ -> ‘/home/hadoop/.bashrc

[root@steven /]# chomd 700 /home/hadoop/

5、修改/home/hadoop目录及其内部所有文件的属主为hadoop,属组为hadoop。

drwxr-xr-x. 21 root root 4096 Aug 23 09:18 var

[root@steven /]# chown -R hadoop:hadoop /home/hadoop/ 

[root@steven /]# ll -a /home/hadoop/

total 12

drwxr-xr-x. 3 hadoop hadoop 78 Sep 10 09:21 .

drwxr-xr-x. 7 root root 68 Sep 10 09:21 ..

-rw-r–r–. 1 hadoop hadoop 18 Sep 10 09:21 .bash_logout

-rw-r–r–. 1 hadoop hadoop 193 Sep 10 09:21 .bash_profile

-rw-r–r–. 1 hadoop hadoop 231 Sep 10 09:21 .bashrc

drwxr-xr-x. 4 hadoop hadoop 39 Sep 10 09:21 .mozilla

6、显示/proc/meminfo文件中以大写或小写S开头的行;用两种方式;

第一种方式:

[root@steven /]# grep ^[sS] /proc/meminfo

SwapCached: 0 kB

SwapTotal: 4194300 kB

SwapFree: 4194300 kB

Shmem: 10108 kB

Slab: 115932 kB

SReclaimable: 54516 kB

SUnreclaim: 61416 kB

第二种方式:

[root@steven /]# grep -i ^s /proc/meminfo 

SwapCached: 0 kB

SwapTotal: 4194300 kB

SwapFree: 4194300 kB

Shmem: 10108 kB

Slab: 115876 kB

SReclaimable: 54516 kB

SUnreclaim: 61360 kB

7、显示/etc/passwd文件中其默认shell为非/sbin/nologin的用户;

[root@steven /]# grep -v "sbin/nologin$" /etc/passwd

root:x:0:0:root:/root:/bin/bash

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

bai:x:1000:1000:bai:/home/bai:/bin/bash

hah:x:1001:1001::/home/hah:/bin/bash

haha:x:1002:1002::/home/haha:/bin/bash

hehe:x:1003:1003::/home/hehe:/bin/bash

hadoop:x:2003:5004::/home/hadoop:/bin/bash

 

8、显示/etc/passwd文件中其默认shell为/bin/bash的用户;

[root@steven /]# grep /bin/bash$ /etc/passwd | cut -d: -f1

root

bai

hah

haha

hehe

hadoop

9、找出/etc/passwd文件中的一位数或两位数;

[root@steven /]# grep “\<[0-9]\{1,2\}\>" /etc/passwd

root:x:0:0:root:/root:/bin/bash

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

lp:x:4:7:lp:/var/spool/lpd:/sbin/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

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

dbus:x:81:81:System message bus:/:/sbin/nologin

rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin

saslauth:x:996:76:Saslauthd user:/run/saslauthd:/sbin/nologin

rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin

ntp:x:38:38::/etc/ntp:/sbin/nologin

tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin

radvd:x:75:75:radvd user:/:/sbin/nologin

gdm:x:42:42::/var/lib/gdm:/sbin/nologin

sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

postfix:x:89:89::/var/spool/postfix:/sbin/nologin

tcpdump:x:72:72::/:/sbin/nologin

10、显示/boot/grub/grub.conf中以至少一个空白字符开头的行;

[root@steven /]# grep “^[[:space:]]\+" /boot/grub/grub.conf 

 sdsdsds 

 ddddd 

 d1323 

 ssssss 

 fffff 

 SADSAFSAFSAF 

 SDSD 

 @#$% 

 !e~都是

 

11、显示/etc/rc.d/rc.sysinit文件中以#开头,后面跟至少一个空白字符,而后又有至少一个非空白字符的行;

[root@steven /]#grep “^#[[:space:]]\+[^[:space:]]" rc.local_bak

 

12、打出netstat -tan命令执行结果中以‘LISTEN’,后或跟空白字符结尾的行;

[root@localhost ~]# netstat -tan |grep ‘LISTEN[[:space:]]\+'

tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN     

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     

tcp 0 0 127.0.0.1:6010 0.0.0.0:* LISTEN     

tcp6 0 0 :::111 :::* LISTEN     

tcp6 0 0 :::22 :::* LISTEN     

tcp6 0 0 ::1:631 :::* LISTEN     

tcp6 0 0 ::1:25 :::* LISTEN     

tcp6 0 0 ::1:6010 :::* LISTEN 

13、添加用户bash, testbash, basher, nologin (此一个用户的shell为/sbin/nologin),而后找出当前系统上其用户名和默认shell相同的用户的信息;

[root@localhost ~]# useradd testbash

[root@localhost ~]# useradd bash

[root@localhost ~]# useradd basher

[root@localhost ~]# useradd -s /sbin/nologin nologin

[root@localhost ~]# grep “^\([^:]\)\+.*\1$" /etc/passwd

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/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

nobody:x:99:99:Nobody:/:/sbin/nologin

systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin

chrony:x:995:991::/var/lib/chrony:/sbin/nologin

nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin

ntp:x:38:38::/etc/ntp:/sbin/nologin

gnome-initial-setup:x:991:986::/run/gnome-initial-setup/:/sbin/nologin

testbash:x:1101:1101::/home/testbash:/bin/bash

bash:x:1102:1102::/home/bash:/bin/bash

basher:x:1103:1103::/home/basher:/bin/bash

nologin:x:1104:1104::/home/nologin:/sbin/nologin

原创文章,作者:白小白,如若转载,请注明出处:http://www.178linux.com/123957

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  • 马哥教育
    马哥教育 2018-09-17 22:25

    建议命令用代码格式 格式化一下显示,建议将命令执行结果也贴出来。这样会更清晰。

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