How do I check whether a variable has an even numeric value?

Question

How should I change this to check whether val has an even or odd numeric value?

val=2
if $((RANDOM % $val)); ...

Answer 1

$ a=4

$ [ $((a%2)) -eq 0 ] && echo "even"
even

$ a=3

$ [ $((a%2)) -eq 0 ] && echo "even"

Answer 2

foo=6

if [ $((foo%2)) -eq 0 ];
then
    echo "even";
else
    echo "odd";
fi

Answer 3

$(( ... )) is just an expression. Its result appears where bash expects a command.

A POSIX-compatible solution would be:

if [ "$(( RANDOM % 2))" -ne 0 ]; 

but since RANDOM isn't defined in POSIX either, you may as well use the right bash command for the job: an arithmetic evaluation compound command:

if (( RANDOM % 2 )); then