Is there a way to block certain command outputs from appearing for specific user classes? For example, I want users to be able to use the show routes command, but I don't want them to see certain routes like "126.96.36.199/24", so when they do a show route, the routes that involve 188.8.131.52/24 will not appear in their output for that command.
No, you cannot restrict access in Junos based on data output.
the security model for user access is based on the hierarchy of the configuration or the access to the commands themselves. Once you have access to the command at that level you will see the results of the command.
Steve Puluka BSEET - Juniper Ambassador IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP) http://puluka.com/home