Question

Write a bash script that will:

Take in three parameters. Display the name of the filename of your shelf program – such as: ”You executed the shell program $0” Display the three parameters in one line or three different lines with text telling the user what the variable is.

Comment all lines as to what they do.

Answer 1

Please let me know if you need more information:-

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*) Display the name of the filename of your shelf program – such as: ”You executed the shell program $0”
echo "You executed the shell program $0"

*) Display the three parameters in one line or three different lines with text telling the user what the variable is.

ss139t@ss139t:~/q157$ cat myScript.sh
#!/bin/bash

#Display the name of the filename of your shelf program

echo "You executed the shell program $0" #Displays the script name to the screen along with message

#start of if conditon
if [ "$#" -lt "3" ];then #Check if the parameters passed to this script is less than three(3)
echo "You must provide Three parameters" #Displays the validation message to screen
exit 1 #Returns from script and exit with return code 1
fi #end of if condition

echo "First parameter is $1"
echo "Second parameter is $2"
echo "Third parameter is $3"

echo "========================================"
#The below code is just to determine the entered parameter is number or non-numeric
re='^[0-9]+$' #regex to make sure supplied value contains only the numbers

if ! [[ $1 =~ $re ]];then
echo "First parameter $1 is non-numeric"
else
echo "First parameter $1 is number"
fi

if ! [[ $2 =~ $re ]];then
echo "Second parameter $2 is non-numeric"
else
echo "Second parameter $2 is number"
fi

if ! [[ $3 =~ $re ]];then
echo "Third parameter $3 is non-numeric"
else
echo "Third parameter $3 is number"
fi

ss139t@ss139t:~/q157$
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Note: if not required , you can ignore from line number : 19

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OUTPUT:-

================

ss139t@ss139t:~/q157$ bash myScript.sh 1 2 xyz
You executed the shell program myScript.sh
First parameter is 1
Second parameter is 2
Third parameter is xyz
========================================
First parameter 1 is number
Second parameter 2 is number
Third parameter xyz is non-numeric
ss139t@ss139t:~/q157$ bash myScript.sh 1 2 3
You executed the shell program myScript.sh
First parameter is 1
Second parameter is 2
Third parameter is 3
========================================
First parameter 1 is number
Second parameter 2 is number
Third parameter 3 is number
ss139t@ss139t:~/q157$

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Please let me know if you need more information:-

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Thanks

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