I wonder if we should have long options as well. Especially the -o appears to be non-obvious as output directory rather than output file. I understand that -d is taken for debug.

We need to print a help text if unknown options or arguments are used.

The needs a prototype added, apparently ($$) is needed.

A function should not second-guess options. All options parsing should be in the scope that calls Getopt::Whatever(), i. e. in this case in the global scope.

Umm... we break the first argument out as apparent file handle ($fh), and then use OUT? Looks inconsistent to me in ll. 116, 118, 119 below.

It appears that in the previous and this iteration of the code, we do not need this function any more - we could just delete it, and rename [[ #l112 | printcert_info($$$) ]] above to printcert($$$), or am I missing something?

$infile should become an argument to this function -- used in l. 131 below.

$infile should become an argument to this function -- used in l. 148 below.

$infile should become an argument to this function, used on line 173 below.

This lacks error handling (out of disk space, lack of permission, ...). Please add. (I'll concede that the previous version of the code did not check stdout write success either...)

we need to add a close($fh) and error checks here.

Hmmm... we use this marker inconsistently depending on whether -o DIR is used or not - is that intentional?

oh, right, missed that it is local. My apologies.

Thanks. As we make the code more complex, making it more maintainable seemed to make sense to me.

this is a place where error checking will also be beneficial - it will report write errors that only occur once we have the buffers flushed.

... or die "SOME FANCY ERROR MESSAGE WITH REASON";