Shell learning: Several common shell exercises

1. Write the shell script and calculate the 1-100;

2.   writing The script requires a number to be entered and then calculated from 1 to enter the number and, if required, if the number entered is less than

3.   writing Script, put /root/ all directories (only one level) are copied to /tmp/ directory;

4.   writing Script, Batch build user and all users belong to users

5.   writing Scripts, intercepting files test.log

6.   writing Script, judging the input of the ip The rules are, , of which 1<n1<255, 0<n2<255, 0<n3<255, 0<n4 <255)

Here are the answers to the exercises:

1. #! /bin/bash

Sum=0

For i in ' seq 1 100 '; Do

sum=$[$i + $sum]

Done

Echo $sum

2. #! /bin/bash

N=0

While [$n-lt "1"]; Do

Read-p "Please input a number, it must greater than" 1 ":" N

Done

Sum=0

For i in ' seq 1 $n '; Do

sum=$[$i + $sum]

Done

Echo $sum

3. #! /bin/bash

For f in ' ls/root/'; Do

If [-D $f]; Then

Cp-r $f/tmp/

Fi

Done

4. #! /bin/bash

Groupadd Users

For i in ' seq 0 9 '; Do

Useradd-g Users User_0$i

Done

For j in ' seq 10 100 '; Do

Useradd-g Users User_$j

Done

5. #! /bin/bash

Awk-f ': ' $0~/abc/{print '} ' Test.log >/tmp/n.txt

Sort-n n.txt |uniq-c |sort-n >/tmp/n2.txt

awk ' $1>10 {print $/tmp/n2.txt} '

6. #! /bin/bash

Checkip () {

If echo $ |egrep-q ' ^[0-9]{1,3}\. [0-9] {1,3}\. [0-9] {1,3}\. [0-9] {1,3}$ '; Then

A= ' echo $ | Awk-f. ' {print '} '

B= ' echo $ | Awk-f. ' {print $} '

C= ' echo $ | Awk-f. ' {print $} '

D= ' echo $ | Awk-f. ' {print $4} '

For n $a $b $c $d; Do

If [$n-ge 255] | | [$n-le 0]; Then

echo "The number of the IP should less than 255 and greate than 0"

Return 2

Fi

Done

Else

echo "The IP you are something wrong, the format is like 192.168.100.1"

Return 1

Fi

}

Rs=1

While [$rs-GT 0]; Do

Read-p "Please input the IP:" IP

Checkip $ip

Rs= ' echo $? '

Done

echo "The IP is right!"

Shell learning: Several common shell exercises