Defining a variable with or without export

Question

What is export for?

What is the difference between:

export name=value

and

name=value

Answer 1

It should be noted that you can export a variable and later change the value. The variable's changed value will be available to child processes. Once export has been set for a variable you must do export -n to remove the property.

$ K=1
$ export K
$ K=2
$ bash -c 'echo ${K-unset}'
2
$ export -n K
$ bash -c 'echo ${K-unset}'
unset