Shell exercises (10)

Exercise 1:User interaction Scripts

Requirements: write a script that, after execution, prints a line that says "Please input a number:", asks the user to enter a value, prints out the value, and then asks the user to enter the value again. Until the user enters "end" to stop.

Reference Answer:

#!/bin/bash# date:2018 March 5 while:d o read-p "Please input a number: (End for exit)" N num= ' echo $n |sed-r ' s/[0-9]//g ' | Wc-c ' if [$n = = "End"] then exit Elif [$num-ne 1] then echo "Please input a number. "Else echo" $n "Fidone

Exercise 2: script transfer

Requirements: a script is written using the method of subtraction, which realizes the function of the message. For example: SH a.sh 1 2, which calculates the result of addition, subtraction, multiplication, and division respectively.

1 The script needs to determine that the two numbers provided must be integers

2 when subtracting or dividing, you need to decide which number is large

3 numbers that need to be reduced with a large number when subtracting

4 division requires a large number divided by a small number, and the result needs to retain two decimal points.

Reference Answer:

#/bin/bash# date: 2018 March 5 If [ $# -ne 2 ];then    echo   "please usage: ./$0 num1 num2."     exit 1fiis_int () {    if echo  "$" |grep -q  [^0-9];then        echo  "$1 is not a  Number. "         exit 1    fi}max () {     if [ $1 -ge $2 ];then        echo  $1    else        echo $2     fi}min () {            if [ $1  -lt $2 ];then        echo $1     Else        echo $2&nbSp;   fi}sum () {    echo  "$1 + $2 = $[$1+$2]"}sub () {    large= ' max $1 $2 '     small= ' min $1 $2 '      echo  "$large  -  $small  = $[$large-$small]"}mul () {     echo  "$1 * $2 = $[$1*$2]"}div () {    large= ' max $1  $2 '     small= ' min $1 $2 '     d= ' echo  ' scale=2;   $large  /  $small "|BC     echo " $large  /  $small  = $ D "}is_int $1is_int $2sum $1 $2sub $1 $2mul $1 $2div $1 $2

Exercise 3: divisible by 3

Requirements: Write a script that calculates all positive integers within 100 that can be divisible by 3

Reference Answer:

#/bin/bash# date:2018 March 5 sum=0for i in ' seq 1 ' do if[$[$i%3]-eq 0];then sum=$[$sum + $i] Fidoneecho "su m= $sum "

Shell exercises (10)