I need to take a Microsoft SQL Server database backup (dump) file and import/restore into a PostgreSQL database. Does anybody have some sort of transform script (maybe a perl/sed/awk script) that could be run on the MSSQL Server backup file, so that it could be restored to the PostgreSQL database? Let's assume the tables have already been created in postgres, but they are all empty.
I would start with this article from the Postgresql site
You could export data from MSSQL in CSV format (using MSSQL Enterprise Manager) and then import the CSV files into Postgresql (here there is an example). I suggest to export one CSV per table, so you can better manage any constraint rule.