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.
As far as i know there are two options:

1. Copy files to uss-filesystem and `grep` there as mentioned above;
works for me.
2. Create an external link
(`~ /usr/sbin/mount -f host.quali.pda -O 'SYNC(120)' mountpoint`)
and `grep` via that link; currently not
working for me because of rights-restrictions.

The `cat`-suggestion works well for a single file, but not for all pds-members (at least i was not able to make it work).