windows - Why is the FOR /f loop in this batch script evaluating a blank line?

Question

I'm trying to write a batch script that obtains (among other things) a list of all of the disk drives the computer has. The basic code looks something like this:

REM Build the list of disk drives to monitor
SETLOCAL enabledelayedexpansion
FOR /f "skip=1 tokens=1 delims=:" %%a in ('"WMIC logicaldisk WHERE drivetype=3 GET deviceid"') do (
    SET "DISK_DATABASES=!DISK_DATABASES!%%a|"
    SET "DRIVES_TO_MONITOR=!DRIVES_TO_MONITOR!%%a:\|"
)

I pretty obviously build two lists with slightly different formats for use later. When I run this, however, the output I get looks something like this:

C|D|E||
C:\|D:\|E:\|:\|

Now, I expect the trailing pipe in both cases and I can manage that, but I'm really confused why there is an extra blank entry in there. If I run the wmic command manually, I can see that there is indeed a blank line at the end of the output, but my understanding is that /f was specifically supposed to ignore blank lines.

If I turn ECHO on, it looks like that last line is just coming in as a carriage return/newline or similar. Is there a way to do what I'm expecting? Am I missing something? I tried to write an if condition in the loop to exclude this last line, but it was... funky and never worked. I appreciate any/all help.

Answer 1

I just came over this topic. I've been using findstr /v to exclude empty lines:

FOR /f "usebackq skip=1 tokens=1 delims=:" %%a in (`WMIC logicaldisk WHERE "drivetype=3" GET deviceid ^| findstr /v /r "^$"`) do (