Question: I have a search I'd like to run against a zOS dataset, and I know how to form the grep command. I have access to the machine via Unix system services, how to I address a dataset from that environment?

Answer: 
No need to cp first. You can cat, tail, grep etc. The thing to remember is the special quoting and that the DSN is preceded by two slashes:

cat "//'s052WX.EO.REXX(MYREXXSOURCE)'" | grep parse

If you look in the UNIX command reference manual under the cp command there’s more info.
* z/OS supports UNIX ([Single UNIX Specification](https://en.wikipedia.org/wiki/Single_UNIX_Specification)) APIs and applications through [USS](https://en.wikipedia.org/wiki/UNIX_System_Services) (**U**NIX **S**ystem **S**ervices).
* The Open Group certifies z/OS as a compliant UNIX operating system – with UNIX/Linux-style hierarchical HFS and zFS file systems.