"End claims" linux-Fifth Test question

1.1Add a userMySQLSpecifyUIDto be888, disable login and do not create home directory.

Useradd-u 888-m-s/sbin/nologin MySQL

1.2Brief IntroductionRAID0 RAID1RAID5 RAID10working principle and characteristics?

RAID 0 at least one hard drive reads and writes fast but without redundancy a piece of bad overall collapsed

RAID 1 only two hard drives read and write relatively poorly there is a hard disk that is redundant but also loses the capacity of a piece of hard disk. A maximum of one hard drive is lost;

RAID 5 minimum three HDD read and write speed between 0 and 1 a hard disk to do backup, a maximum loss of a hard disk;

RAID 10 minimum four block hard disk read and write performance good loss two hard disk to do redundancy maximum loss of two hard drives;

1.3List/usr/The amount of space occupied by each subdirectory under the directory

Df-h/usr/*

1.4fill in the blanks questions: ABlock2TBthe hard drive is not consideredHotsparethe case of doingRAID0,RAID1,RAID5the rear space is respectively(no redundancy is all for capacity: -), (loss of a piece of hard disk to do redundancy, capacity: A), (divided into One-third to do redundancy, capacity: A). 1.5name the common interface type for the disk.

SATA SAS PCI-E

1.6sedCommand Exercises

[[Email protected]~]# cat/tmp/passwd

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

BIN:X:1:1:BIN:/BIN:/SBIN/NOLOGINDAEMON:X:2:2:DAEMON:/SBIN:/SBIN/NOLOGINADM:X:3:4:ADM:/VAR/ADM:/SBIN/NOLOGINLP: X:4:7:lp:/var/spool/lpd:/sbin/nologin

sync:x:5:0:sync:/sbin:/bin/syncshutdown:x:6:0:shutdown:/sbin:/sbin/shutdownhalt:x:7:0:halt:/sbin:/sbin/ Haltmail:x:8:12:mail:/var/spool/mail:/sbin/nologinuucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin

Cat >passwd.txt<<eof

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

BIN:X:1:1:BIN:/BIN:/SBIN/NOLOGINDAEMON:X:2:2:DAEMON:/SBIN:/SBIN/NOLOGINADM:X:3:4:ADM:/VAR/ADM:/SBIN/NOLOGINLP: X:4:7:lp:/var/spool/lpd:/sbin/nologin

Sync:x:5:0:sync:/sbin:/bin/syncshutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

Halt:x:7:0:halt:/sbin:/sbin/haltmail:x:8:12:mail:/var/spool/mail:/sbin/nologin

Uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin

Eof

1.6.1Remove all spaces at the beginning of each line

Sed ' s#^[]# #g ' Passwd.txt

1.6.2enclose all lowercase letters in parentheses ().

[[Email protected] etc]# sed ' s#[a-z]# (&) #g ' passwd

1.6.3Delete the first three rows

Sed '/root/,/bin/d ' passwd

1.6.4ShowBin-haltlines between the beginning

Sed-n '/bin/,/halt ' passwd

1.7ShellExam Questions1.7.1CentOSthe defaultShell

#!/bin/bash

1.7.2The known script looks like this

#cat test.sh #!/bin/bash user= ' WhoAmI '

Ask SH test.sh after the echo $user return results?

null; user is not an environment variable

[Email protected] ~]# sh ceshi.sh && echo $user

[Email protected] ~]#

1.7.3 Shellvariables are divided into

1. Environment variables

2. Common variables

3. Special variables

1.7.4describe the type or effect of the following variables

Export oldgirl=oldboyedu oldgirl is an environment variable, passwd is a special variable

$ A file for the current shell

$ $ The third parameter of the current shell

$# all parameters of the current shell

$? Show whether the command executed successfully

1.7.5find the wrong variable name below

①x

②name

③password

④1jia

⑤123

⑥z_123

6, because a variable can only start with a letter or an underscore, rather than a letter or underscore

1.7.6Write2environment variable configuration file and a1List of

/etc/profile

/etc/bashrc

/etc/profile.d

1.7.7write the corresponding script according to test instructions

Determine if the/data directory exists, enter the directory and view the file properties

#!/bin/bash

if [-d/data]

Ll/data

Fi

Determine if the/etc/hosts file exists, and then copy the file to the/tmp directory.

#!/bin/bash

if [-f/etc/hosts];then

\cp/etc/hosts/tmp

Fi

[Email protected] ~]# ls-lrt/tmp/hosts

-rw-r--r--1 root root 188 Nov 00:49/tmp/hosts

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"End claims" linux-Fifth Test question