Don't confuse 'isql' which is the command-line tool that comes with ASE with 'DBISQL or dbisql' (Interative SQL GUI) that comes with ASE, IQ and SQL Anywhere.
You are refererencing dbisql/DBISQL in your use of 'output' statements, which 'isql' does not use.
Also from some of the other responses, there is no reason that you cannot use other delimiters (e.g. tab, '|', etc) in the BCP tool (even through views) to output the data.
Tools such as Excel can easliy import different delimiters and ignore the double quotes. Often other delimiters are used as sometimes the data also contains double quotes (and then you need to find a way to 'escape' the embedded quote). Better to just skip needing double quotes around the strings and use a different delimiter that doesn't show in the data.
Are you sure you really need double quotes around strings and commas as the delimiter? What is the file being generated for?
Chris