How to gzip a dataset in SAS EG？

[qc1]

My code is:
options compressed=yes;
libname public "path/to/public";
x "gunzip path/to/public/sale_21.sas7bdat.gz";

proc append base=public.sale_21 data=public.new_21 force;
run;

x "gzip path/to/public/sale_21.sas7bdat";


At the beginning, there are two datasets under public folder: one compressed sale_21.sas7dbat.gz and one uncompressed new_21.sas7bdat

I want to uncompressed sale_21 add data from new_21 to the end of sale_21, and then gzip it back. The public folder should still have two datasets.

But after I run my program, it create another dataset, now my public folder has three files : one compressed sale_21.sas7bdat.gz and one uncompressed sale_21.sas7bdat and the original new_21.sasbdat. Why it created additional datasets? What should the codes be ??

Thanks SO much!! Any help would be greatly appreciated!

[Tom · Accepted solution]

Are you asking how the commands gzip and gunzip work?

Shouldn't that be asked somewhere else?

If you want to see what messages the operating system is generating when you run those commands I recommend NOT using the X command.  Instead use a PIPE so your can read the responses and at least write them to the SAS log.

data _null_;
  infile
   "gunzip path/to/public/sale_21.sas7bdat.gz &2>1"
    pipe
  ;
  input;
  put _infile_;
run;

If that does not work then just try opening a terminal window to the SAS server and running the commands directly in the terminal window and observe the behavior.  Perhaps your system has defined an alias for gzip that causes it to not replace the existing file but leave it behind.