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Taking inputs from user in a script

Here we will see how to take input from user in a script with the help of read command.

#!/bin/bash

  • Lets try multiplication of two numbers which the user enters.
  • What read does is ? It takes values by user on stdin.
  • It prompt the user to input any value on stdin.
  • -p is used to display a prompt.

read -p "First number:" value1

  • This will give a prompt as "First number" and store the value in variable "value1"

echo

  • Will display a blank line.

read -p "Second number:" value2

  • This will give a prompt as "Second number" and store the value in variable "value2"

echo

  • Will display a blank line.

read -sn1 -p "Press any key to see the answer..."

  • Just to make it bit more interactive lets add one more thing.
  • -s means silent mode that is if any value is pressed it will not be displayed on the screen like as in the password.
  • -nX means how many characters.
  • X here is one that is any key.

let answer=$value1*$value2

  • Lets get these values multiplied and store the result in answer variable.

echo -e "\n Result is: $answer"

  • This will get the result printed.
  • Observed one thing in the last read command we haven't added any variable to save the input.
  • But read still stores the value in some variable called $REPLY
  • If we want to then we can overwrite the vaule of $REPLY by adding a variable.
  • If you want to see what to entered to see the result then you can use echo $REPLY.

sunny@sunny-workstation bin]$ ./6_read_command.sh 
First number:44

 Second number:34

 Press any key to see the answer...
 Result is: 1496
sunny@sunny-workstation bin]$

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