passwords with special characters

[javelina73]

Describe the bug
when using this script with use_credentials and the credentials have special characters it will fail with error "binary operator expected" and the script will exit with error "mysql command has failed (bad credentials?)"

To Reproduce
Steps to reproduce the behavior:

1. create a mysql user account with a password that contains special characters
2. configure this script with use_credentials using the credentials created in step 1

Expected behavior
The prefreeze script should execute successfully regardless of characters in the password.

Desktop (please complete the following information):

• OS: rhel 8.7
• veeam v12
• mysql 8.0

Resolution: change the following from:
if [ -n $use_credentials ]; then
opts="$opts $use_credentials"
fi

To:

if [[ -n $use_credentials ]]; then
opts="$opts $use_credentials"
fi