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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 ...
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Sourcing a variable

Lets create a file with following content:

 #!/bin/bash
echo "$var1"

Assign a value to a local variable var1

sunny@sunny-workstation bin]$ var1=sunny-workstation
sunny@sunny-workstation bin]$ chmod +x 2_simple_script.sh 


When you will run this script it will state nothing. That's because script doesn't know anything about var1 variable and that it exists in shell environment.

sunny@sunny-workstation bin]$ ./2_simple_script.sh 

 sunny@sunny-workstation bin]$

But if we source this script via . or source built-in command it will show the output as the script will run in the same environment as our shell

sunny@sunny-workstation bin]$ . ./2_simple_script.sh 
sunny-workstation
sunny@sunny-workstation bin]$ source 2_simple_script.sh 
sunny-workstation
sunny@sunny-workstation bin]$

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