The OpenVMS rename command is more handy (imho) than the windows or unix variants, because it can bulk change chuncks of the full file name. Such as 'name', 'type' or (sub)directory.
For example:
$ rename *.dat *.old
That's great but it will not change within the chunks (components) like the name part requested here. For that, the classic DCL approach is a quick loop, either parsing directory output (Yuck!) or using F$SEARCH. For example:
$loop:
$ file = f$search("*EDI.LIS")
$ if file .eqs. "" then exit
$ name = f$parse(file,,,"name","syntax_only") ! grab name component from full name
$ rename/log 'file' 'name'_demo ! rename 'fills in the blanks'
$ goto loop
Personally I use PERL one-liners for this kind of work. (and I test with -le using 'print' instead of 'rename' first. :-)
$ perl -e "for (<*edi.lis>) { $old = $_; s/_edi/_edi_demo/; rename $old,$_}"
Enjoy! Hein