LINUX Scripts de Bash Shell. Exercise 1 - Working with Files

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1 LINUX Scripts de Bash Shell Exercise 1 - Working with Files Write a script that will ask the user for a directory name, which the script will create. Change the working directory to the new directory and tell the user where you are using the pwd command. Next use touch to create a few les followed by displaying the lenames. Use echo and redirection to put some content into the les and show the user the content. Finally, say goodbye to the user to end the script. leslab - demos several simple commands to create a directory, cd to that directory, echo 'pwd' create several les, put data into the les and list the les echo "Welcome to File Creator" echo "What name do you want to give to the new directory?" Get the new name from the user read dirname make the directory mkdir $dirname change the current working directory to the new directory cd $dirname announce where we are echo "This directory is called 'pwd' " create some les touch le1 le2 le3 put content into the les, the directory and le name echo "This is $dirname/le1" > le1 echo "This is $dirname/le2" > le2 echo "This is $dirname/le3" > le3 announce the le names echo "The les in $dirname are: " ls -hl show the content of the les echo "The content of the les are: " cat le1 cat le2 cat le3 echo "Goodbye" Exercise 2 - Functlons Write a script that asks the user for a number (1,2 or 3) which is used to call a function with that number in its name. The function displays a message with the function number within it, for

2 example, "This message is from function 3." functionlab demonstrates functions and script parameters Functions func1(){ echo " This message is from function 1" func2(){ echo " This message is from function 2" func3(){ echo " This message is from function 3" Main script prompt the user echo "Enter a number from 1 to 3" get the user's choice read choice the number chosen by the user is added to the name func to select funcl, func2 or func3 the function call is simply the name of the function func$choice put out a line feed echo " " Exercise 3 - Arithmetic Write a script that will act as a simple calculator for add, subtract, multiply, and divide; each operation should be in a function of its own. Any of the three methods for bash arithmetic, let, expr or $((..)), may be used. The user should pass as an argument in the command line a letter (a,s,m or d) and two numbers. The letter will be used to determine which operation will be performed on the two numbers entered. lf one or more of the three parameters is left out, display a usage message. Finally display the answer.

3 arithmeticlab demonstrates arithmetic, functions and simple if clauses three methods are used for arithmetic. the exercise requires only one. the three methods are : 1)let 2) expr 3) $(( ) The user will input a letter and two numbers. the letter will be a(dd), s(subtract), m(ultiply) or d(ivide) to select an arithmetic operation. Functions. must be befare the ma1n part of the script adder (){ method 1. use let let answer1=($fnumber + $snumber) method 2. use expr answer2=$( expr $fnumber + $snumber ) method 3 use $((...) answer3=$(( $fnumber + $snumber )) end adder function subtracter (){ method 1. use let let answer1=($fnumber - $snumber) method 2. use expr answer2=$( expr $fnumber - $snumber ) method 3 use $((...) answer3=$(( $fnumber - $snumber )) end subtracter function multiplyer (){ method 1. use let let answer1=($fnumber * $snumber) method 2. use expr answer2=$( expr $fnumber * $snumber ) method 3 use $((...) answer3=$(( $fnumber * $snumber )) end multiplyer function divider (){ method 1. use let let answer1=($fnumber / $snumber) method 2. use expr

4 answer2=$( expr $fnumber / $snumber ) method 3 use $((...) answer3=$(( $fnumber / $snumber )) end divider function End of functions Main part of the script check that user provided a letter and two numbers does not check to see if the user put in an incorrect letter which will simply display messages without an answer if [ $ -lt 3 ] echo "" echo "Usage : Provide an operation (a,s,m,d) and two numbers " echo "" exit set the input numbers to variables to pass to the functions fnumber=$2 snumber=$3 if [ $1 = "a" ] adder if [ $1 = "s" ] subtracter if [ $1 = "m" ] multiplyer if [ $1 = "d" ] divider Present the answers for all three methods echo "Method 1 Answer is $answer1"

5 echo "Method 2 Answer is $answer2" echo "Method 3 Answer is $answer3" Exercise 4 - BMI Write a script bmi.sh to calculate the user's body mass index (BMI) to the nearest integer, as well as the user's weight class. BBBBBB = wwwwwwwwhtt heeeeeehtt 2 Delgadez moderada 16,00-16,99 Delgadez leve 17,00-18,49 Normal 18,5-24,99 Sobrepeso 25,00-27,49 Preobeso 27,50-29,99 Obesidad 30,00-32,49 Obesidad leve 32,50-37,49 Obesidad media 35, Obesidad mórbida 40,00 Exercise 5 - fact Write a script factoriali.sh to calculate the factorial of a number in iterative form. Write a script factorialr.sh to calculate the factorial of a number in recursive form.