LOG=~/log/myapp.log

[ ! -d $LOG_DIR ] && mkdir ~/LOG_DIR

prompt="enter your variable value"

read -p $prompt var
echo -e "${var}\t${mydate}" >> $LOG

#########
usr_input() {
# user input; return an answer or default
question=$1
if [ $# -gt 1 ]; then
    default=$2
    read -p "$question [$default]? " answer
    if [ "$answer" == "" ]; then
        answer=$default
    fi
else
    read -p "$question? " answer
fi
echo $answer
}