not an expert of korn-shell, but what you want is capturing STDERR.

If there is no direct way to do it, but you could redirect STDERR to STDOUT and capture STDOUT.

No idea if you need backticks° in ksh then!¹

(I would do the whole task completely within Perl not in ksh²)

HTH (otherwise others will know =)

updates

°) ksh seems to support $() for backticks

¹) normally errors are piped into a file like here, bash can use backticks to capture STDOUT

²) should be mentioned that this is not a Perl question!