Shell script for creating user with password in postgres failing with quotes - bash

Question

I am trying to create a shell script to bootstrap new DBs.
I am able to create users, grant privileges and do all actions, except running any queries with passwords. The single quotes in shell script creates statements which postgres is not accepting.
Because of this, we cannot completely automate this process.
Below is one of the postgres line used in shell script.
PGPASSWORD=change123 psql -h $DB -p 5432 -d postgres -U root -c \"CREATE USER $(echo "$j" | cut -d "_" -f1)dbuser WITH PASSWORD \'$(echo $DBPASSWD|base64 --decode)\';\"
When executing the above script, the command is converted as
psql -h testdb -p 5432 -d postgres -U root -c '"CREATE' USER admindbuser WITH PASSWORD ''\''ZnuLEmu72R'\'''
where I want the command to be like
psql -h testdb -p 5432 -d postgres -U root -c "CREATE USER admindbuser WITH PASSWORD 'ZnuLEmu72R';"
Any help is very much appreciated. I want some help in guiding how to modify the line in shell so as to achieve the required command.

Answer 1

Change
PGPASSWORD=change123 psql\
-h $DB \
-p 5432 \
-d postgres \
-U root \
-c \"CREATE USER $(echo "$j" | cut -d "_" -f1)dbuser WITH PASSWORD \'$(echo $DBPASSWD|base64 --decode)\';\"
to
PGPASSWORD=change123 psql \
-h "$DB" \
-p 5432 \
-d postgres \
-U root \
-c "CREATE USER ${j%%_*}dbuser WITH PASSWORD '$(printf '%s' "$DBPASSWD" | base64 --decode)';"