accessing a number from a file in bash scripting

Question

I have a file abc.out. This file only has a number written in it. I want to access this file, store this number in a variable and use an if condition to check some condition. How do I do this in my bash script?

Answer 1

You can use the followign syntax.

NUM=$(cat abc.out)

or

NUM=`cat abc.out`

Answer 2

You can read the file contents into a variable with:

var=$(< filename)

or:

read var < filename