Homework exercises After class

Related exercises:

1. The contents of the File1 file are: "1 2 3 4 5 6 7 8 9 10" Calculates the sum of all numbers

Echo $[1+2+3+4+5+6+7+8+9+10]

echo "1+2+3+4+5+6+7+8+9+10" | Bc

Computer Demo

[[email protected] desktop]# echo $[1+2+3+4+5+6+7+8+9+10]

55

[Email protected] desktop]# echo "1+2+3+4+5+6+7+8+9+10" | Bc

55

[Email protected] desktop]#

2, processing string "Xt.,l 1 jr#! $mn 2 c*/fe3 uz4", keep only the numbers and spaces

echo "Xt.,l 1 jr#! $mn 2 c*/fe3 uz4" | Tr-d "xt.,ljr#! $MNC */feuz"

Computer Demo

[[email protected] desktop]# echo "Xt.,l 1 jr#! $mn 2 c*/fe3 uz4" | Tr-d "xt.,ljr#! $MNC */feuz"

echo "Xt.,l 1 jr#bcmn2 c*/fe3 uz4" | Tr-d "Xt.,ljr#bcmnc*/feuz"

1 2 3 4

[Email protected] desktop]#

3. Display the path variable in a separate row for each directory

echo $PATH | TR ":" \ n "

Computer Demo

[Email protected] desktop]# echo $PATH | TR ":" \ n "

/usr/lib64/qt-3.3/bin

/usr/local/sbin

/usr/sbin

/sbin

/usr/local/bin

/usr/bin

/bin

/root/bin

[Email protected] desktop]#

4. Delete blank lines of the specified file

Cat/root/install.log | Tr-s "\ n" "Use the-S loop"

Computer Demo

[Email protected] desktop]# Cat/root/install.log | Tr-s "\ n"

{

333

Anaconda-ks.cfg

Desktop

Documents

Downloads

F1

F22

F99

F[A,B,C,D,E,F]

History.log

Install.log

Install.log.syslog

Music

Nusers

Pictures

Public

Templates

Videos

[Email protected] desktop]#

5. Display each word (letter) in the file in a separate line with no blank lines

Cat/root/install.log | TR "" \ n "| Tr-s "\ n"

Computer Demo

[Email protected] desktop]# Cat/root/install.log | TR "" \ n "| Tr-s "\ n"

{

333

Anaconda-ks.cfg

Desktop

Documents

Downloads

F1

F22

F99

F[A,B,C,D,E,F]

History.log

Install.log

Install.log.syslog

Music

Nusers

Pictures

Public

Templates

Videos

6, create user Tiantian, additional group is bin and root, default shell is/bin/csh, annotation information is "Tiantian distribution"

Useradd-g bin,root-s/bin/csh-c "Tiantian Distribution" Tiantian

Computer Demo

[Email protected] desktop]# useradd-g bin,root-s/bin/csh-c "Tiantian Distribution" Tiantian

Rtkit:x:499:499:realtimekit:/proc:/sbin/nologin

Avahi-autoipd:x:170:170:avahi Ipv4ll Stack:/var/lib/avahi-autoipd:/sbin/nologin

Vcsa:x:69:69:virtual Console Memory Owner:/dev:/sbin/nologin

Abrt:x:173:173::/etc/abrt:/sbin/nologin

Rpcuser:x:29:29:rpc Service User:/var/lib/nfs:/sbin/nologin

Nfsnobody:x:65534:65534:anonymous NFS User:/var/lib/nfs:/sbin/nologin

Haldaemon:x:68:68:hal Daemon:/:/sbin/nologin

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

Apache:x:48:48:apache:/var/www:/sbin/nologin

SASLAUTH:X:498:76:SASLAUTHD User:/var/empty/saslauth:/sbin/nologin

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

Mysql:x:27:27:mysql Server:/var/lib/mysql:/bin/bash

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

Pulse:x:497:495:pulseaudio System Daemon:/var/run/pulse:/sbin/nologin

Sshd:x:74:74:privilege-separated Ssh:/var/empty/sshd:/sbin/nologin

Tcpdump:x:72:72::/:/sbin/nologin

Tianya:x:500:500:tianya:/home/tianya:/bin/bash

Gentoo:x:501:501:gentoo disttibuution:/home/gentoo:/bin/csh

Tian:x:502:502::/home/tian:/bin/bash

Tiantian:x:503:503:tiantian distribution:/home/tiantian:/bin/csh

[Email protected] desktop]# ^c

[Email protected] desktop]#

7. Create the following user, group, and group memberships

Group with the name Admins

User Natasha, using admins as a subordinate group

User Harry, also use admins as a subordinate group

User Sarah, no interactive login system, and not a member of admins, Natasha,harry,sarah password is CentOS

1 #!/bin/bash

2 groupadd Admins

3 useradd-g Admins Natasha

4 useradd-g Admins Harry

5 Useradd-s/sbin/nologoin Sarah

6 echo "CentOS" | passwd--stdin Natasha

7 echo "CentOS" | passwd--stdin Harry

8 echo "CentOS" | passwd--stdin Sarah

Computer Demo

[Email protected] desktop]# Nano f1.xt

[email protected] desktop]# cat F1.XT

#!/bin/bash

Groupadd Admins

USERADD-G Admins Natasha

Useradd-g Admins Harry

Useradd-s/sbin/nologoin Sarah

echo "CentOS" | passwd--stdin Natasha

echo "CentOS" | passwd--stdin Harry

echo "CentOS" | passwd--stdin

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Homework exercises After class