zip is appending instead of replacing

[mightyscotchpine]

I'm having trouble with zipping on a client's SCO OpenSever 5 machine.
I've got two files, xyz.dat and xyz.zip.
I'm doing

zip xyz xyz.dat

For some reason, SCO is appending xyz.dat to xyz.zip, instead of replacing it.
I did the same thing on my server, and it replaces it.
Has anyone out there seen this???
---Thanks.

 

[patw]

Do you mean gzip?

Try gzip xxx > yyy

 

[mightyscotchpine]

PatW:

No, just plain old zip.
I'm trying to find out why an existing script has started to act funny.
Part of the script zips a file into a file w/ a predefined name. This file usually gets replaced.
For some reason, the zip portion of the script is appending to the file instead.

We have many other servers running the same script and getting the expected results.
Have you ever heard of a bug like this?
I already had to reboot - didn't help.

Thanks.