[Linux] Shell Script check value enable/disable

#!/bin/sh
CHECK_FILE="/var/value_check"
CHECK_ENABLE=`cat $CHECK_FILE`
echo "CHECK_ENABLE=$CHECK_ENABLE"
if [ -f $CHECK_FILE -a -n $CHECK_ENABLE ]; then
        if [ $CHECK_ENABLE -eq 1 ]; then
                echo "enable";
        else
                echo "disable 1";
        fi
else
        echo "disable 2";
fi