Solved

NUL

Posted on 2011-03-17
4
677 Views
Last Modified: 2012-05-11
Hi, can you please explain to me what is "NUL"? Google it but no luck.
set p=%1

if not exist %p%\nul mkdir %p%

Open in new window

Thanks
0
Comment
Question by:zhshqzyc
  • 2
4 Comments
 
LVL 3

Expert Comment

by:OrenRozen
ID: 35156342
0
 
LVL 43

Accepted Solution

by:
Steve Knight earned 50 total points
ID: 35156348
Well NUL is a device that eats any input sent to it, e.g.

dir > NUL

results in no output unless there are errors,

dir > NUL 2>&1

says to send standard output to NUL and any errors (2>) to same place.

As a file check like this "NUL" exists everywhere so they have used it to check if a directory exists.  

if exist %p% mkdir %p%

then it would also check if a file of the same name existed for instance.

You could just do:

mkdir  "%~1" >NUL 2>&1

The ~ removes the quotes if existing so they can be re-added to make sure they are there for a path with spaces in.

Steve
0
 
LVL 43

Expert Comment

by:Steve Knight
ID: 35156354
Didn't notice only 50 points :-(
0
 
LVL 13

Expert Comment

by:Rick
ID: 35156356
0

Featured Post

Courses: Start Training Online With Pros, Today

Brush up on the basics or master the advanced techniques required to earn essential industry certifications, with Courses. Enroll in a course and start learning today. Training topics range from Android App Dev to the Xen Virtualization Platform.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

One of my most closely kept secrets is revealed in this discussion How to output text on the same line This question was recently posted in EE by Simon336697 (http://www.experts-exchange.com/Programming/Languages/Scripting/Shell/Batch/Q_2459…
Being a system administrator some time we require to do things remotely, one of them is installing software. Here I am going to tell you how to install software through wmic (Windows management instrument console). I am not at all saying that this i…
Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, just open a new email message. In the To field, type your recipient's fax number @efaxsend.com. You can even send a secure international fax — just include t…
Two types of users will appreciate AOMEI Backupper Pro: 1 - Those with PCIe drives (and haven't found cloning software that works on them). 2 - Those who want a fast clone of their boot drive (no re-boots needed) and it can clone your drive wh…

813 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

15 Experts available now in Live!

Get 1:1 Help Now