The **SA** account is a system administrator on the SQL Server instance that gets created during setup. After creating your SQL Server container, the `MSSQL_SA_PASSWORD` environment variable you specified is discoverable by running `echo $MSSQL_SA_PASSWORD` in the container. For security purposes, change your SA password.

1. Choose a strong password to use for the SA user.

1. Use `docker exec` to run **sqlcmd** to change the password using Transact-SQL. Replace `<YourStrong!Passw0rd>` and `<YourNewStrong!Passw0rd>` with your own password values.

   ```bash
   sudo docker exec -it sql1 /opt/mssql-tools/bin/sqlcmd \
      -S localhost -U SA -P '<YourStrong!Passw0rd>' \
      -Q 'ALTER LOGIN SA WITH PASSWORD="<YourNewStrong!Passw0rd>"'
   ```

   ```PowerShell
   docker exec -it sql1 /opt/mssql-tools/bin/sqlcmd `
      -S localhost -U SA -P "<YourStrong!Passw0rd>" `
      -Q "ALTER LOGIN SA WITH PASSWORD='<YourNewStrong!Passw0rd>'"
   ```