The shell judges whether the database username and password are correct

#!/bin/bash  

DB_PASSWORD=""  
DB_PASSWORD_LEN=""  
SQL_RESULT=""  
SQL_RESULT_LEN=""  

#use a function to get or set the DB_PASSWORD  

# .........  


DB_PASSWORD_LEN=${#DB_PASSWORD}  
#According to the length to determine whether the password is empty, use different statements to process  

if [[ ${DB_PASSWORD_LEN} -eq 0 ]];then  
    SQL_RESULT=${mysql -u ${DB_USER} -e quit 2>&1}  
else  
    SQL_RESULT=${mysql -u ${DB_USER} -p${DB_PASSWORD} -e quit 2>&1}  
be  
#The -p and {DB_PASSWORD} must be next to each other, otherwise you will be prompted to enter the password  


#If the password is correct, SQL_RESULT_LEN is 0  

SQL_RESULT_LEN=${#SQL_RESULT}  

if[[ ${SQL_RESULT_LEN} -eq 0 ]];then
  echo "Right Password !"  
else  
  echo "Wrong Password !"  
be