For those MUMPS veterans. you can also use the $ZSEARCH function. As in the example:

  NEW $NAMESPACE
  SET $NAMESPACE="USER"
  SET file=$ZSEARCH("i*")
   WHILE file'="" {
       WRITE !,file
       SET file=$ZSEARCH("")
   }
   WRITE !,"That is all the matching files"
   QUIT

I think this one will be faster

The second option that Marc Mundt stated is the simplest and most readable IMHO. The $PIECE pseudo variable could be a little expensive in performance:

set lst="" for i=1:1:someNumber set $PIECE(lst,",",i)=myval

You can run a script that back-up all your CACHE.DAT files from alpha to your dev server.

You may also use $QS and $QL functions to calculate the number of subscripts and lengths of a global reference

Can ZPM run in Cache' ?

Tried to install ZPM on Cache' but failed:

%SYS>D $system.OBJ.Load("/tmp/deps/zpm.xml","ck")Load started on 04/21/2021 11:30:27
Loading file /tmp/deps/zpm.xml as xml
Imported class: %ZPM.Installer
Compiling class %ZPM.Installer
Compiling routine : %ZPM.Installer.G1.MAC
ERROR #6353: Unexpected attributes for element Import (ending at line 9 character 45): Recurse
  > ERROR #5490: Error reported while running generator for method '%ZPM.Installer:setup'
    > ERROR #5030: An error occurred while compiling class %ZPM.Installer
Compiling routine %ZPM.Installer.1
ERROR: Compiling method/s: ExtractPackage
ERROR:  %ZPM.Installer.1(3) : MPP5610 : Referenced macro not defined: 'FileTempDir'
 TEXT:   Set pFolder = ##class(%File).NormalizeDirectory($$$FileTempDir)
ERROR: Compiling method/s: Make
ERROR:  %ZPM.Installer.1(7) : MPP5610 : Referenced macro not defined: 'FileTempDir'
 TEXT:     Set tmpDir = ##class(%File).NormalizeDirectory($$$FileTempDir)
%ZPM.Installer.1.INT(79) ERROR #1002: Invalid character in tag : '##class(%Library.File).NormalizeDirectory($$$FileTempDir)' : Offset:61 [zExtractPackage+1^%ZPM.Installer.1]
 TEXT:   Set pFolder = ##class(%Library.File).NormalizeDirectory($$$FileTempDir)
%ZPM.Installer.1.INT(117) ERROR #1002: Invalid character in tag : '##class(%Library.File).NormalizeDirectory($$$FileTempDir)' : Offset:62 [zMake+4^%ZPM.Installer.1]
 TEXT:     Set tmpDir = ##class(%Library.File).NormalizeDirectory($$$FileTempDir)
Detected 5 errors during load.