Check for correct password in PostgreSQL

Check if a ROLE has the correct password, and change if it isn't:

1:  #!/bin/bash                                                                                                                    
2:  DB_USER='icinga'  
3:  DB_PASSWORD='Jaht5aChkib2The5iA'  
4:  SALT=$DB_USER  
5:  MD5_PASSWORD=$(echo -n ${DB_PASSWORD}${SALT} | md5sum | cut -d" " -f1)  
6:  PASSWORD_HASH="md5${MD5_PASSWORD}"  
7:  CURRENT_PASS=$(psql -tA -c "SELECT passwd FROM pg_shadow WHERE usename = '${DB_USER}';")  
8:    
9:  if ! [ $CURRENT_PASS == $PASSWORD_HASH ]; then  
10:    psql -tA -c "ALTER ROLE ${DB_USER} WITH PASSWORD '${DB_PASSWORD}';"  
11:  fi  

Note: to be run locally as postgres user.