Question

How to determine if there is a user in mysql in BASH ?

if [ "$NAME_USER" == ???? ]; then
  echo "User exists in MySQL"
else
  echo "User no exists in MySQL"
fi

Answer 1

while read User; do
    if [[ "$NAME_USER" == "$User" ]]; then
        echo "$User exists in MySQL"
        break
    fi
done < <(mysql -B -N -e 'use mysql; SELECT `user` FROM `user`;')

if [[ "$NAME_USER" != "$User" ]]; then
    echo "$NAME_USER does not exists in MySQL"
fi