How to read the file content into a variable in one go?

Question

In Java, if you know for certain a file is very small, you can use readBytes() method to read the content in one go instead of read it line by line or using buffer.

Just wondering in shell script, I know we can do something like:

    while read line     do       echo $line       LINE = $line     done < "test.file"     echo $LINE 

If my test.file is like:

testline1 testline2 testline3 

This only gives me the last line to $LINE. $LINE contains "testline3".

My question is: How can I read the whole file with multiple lines into one single variable,so I can get $LINE="testline1\ntestline2\ntestline3"?

Answer 1

Process the lines inside the loop instead of after it. If you really need the file in a variable:

var=$(<file)