Shareasale documents the file format in their help center: Help Center » Knowledgebase » Affiliate Topics » Product Links » Datafeeds
A comma-separated-values file is a series of lines, each line being one "record" in the file. Each lines has fields in a specified order, the fields are what is separated by the '|' characters. The first field is the Product ID, the second field is the Product Name, the third field is the Merchant ID, the fourth field is the Merchant Name, and so forth. The exact ordering of values in the file are are documented in the Shareasale help center.