CODEWITHSUNDEEP
windowsbatch-filecmdfqdn
Jatin
Jatin

Reputation: 1997

how to stop echo command from displaying variables which are not set?

I am working on an application that requires my users to share their fully-qualified-domain-name of their windows machine.

To help my users to extract their machine's FQDN, I want to share simple command line steps that they can copy/paste and execute on their terminals to get the result.

I was thinking of below command to extract local machine's FQDN:

echo %COMPUTERNAME%.%USERDNSDOMAIN%

But there are few problems of this command.

  1. It gives output in ALL CAPS. (I can live with it)

  2. It gives incorrect output if the variable is not set.

For example:

If USERDNSDOMAIN value is not set, then, you'll get following output:

echo %COMPUTERNAME%.%USERDNSDOMAIN% //<- Run this on cmd prompt

ClientComputerName.%USERDNSDOMAIN% //<- wrong output: Notice '%USERDNSDOMAIN%' is appended in o/p

Is there any way to stop echoing a variable if it's value is not set?

Please note that I want to extract "fully qualified domain name" of my windows machine through CMD prompt only.

Upvotes: 0

Views: 1341

Answers (2)

Ben Personick
Ben Personick

Reputation: 3264

1st, please note that the "USER DNS Domain" is NOT the domain the computer is joined to, it is the domain the USER who is logged in belongs to.

If you log in as a user from a trusted domain, or a child or parent domain, then it will display that domain.

So, if you log in as a LOCAL account it will be blank (likely you are running into this)

There is a fairly simple way to get the actual computer domain however, by using NLTest. (For the like of me I could never figure out why Microsoft didn't pre-populate a variable with this info.)

At the CMD Line simply dump this into the command prompt (I believe you will need to run with admin privileges but I haven't tested):

FOR /F "tokens=3" %_ IN ('nltest /DOMAIN_TRUSTS /PRIMARY ^|FIND /I "0:"') DO @(ECHO.%COMPUTERNAME%.%_)

The result will be in all caps because that is how Microsoft displays this info.

Here is an example output:

MYLAPTOP.USERS.MYDOMAIN.LOCAL

But on-re-read you want something the users know how to do themselves, so ymmv if you could just send a reference email, or hand it to them each time they need it.

If you just wan this info and other info easily available you could use BGInfo or other options like that to set the desktop background.

Alternatively you could change the logon scripts to generate a simple text file with all the info each time the user logs on, and placed in a certain folder you tell them to look in.

Upvotes: 0

lit
lit

Reputation: 16256

You can get the FQDN name using PowerShell.

=== Get-FQDN.bat

@ECHO OFF
FOR /F %%A IN ('powershell -NoLogo -NoProfile -Command ^
    "([System.Net.Dns]::GetHostByName($Env:COMPUTERNAME)).HostName"') DO (
    SET "THEFQDN=%%A"
)
ECHO %THEFQDN%

If you have multiple users, then you surely have some way to get programs and batch files installed on them. Once this batch file script is installed into a directory on the user's PATH, it is a one-line command.

Get-FQDN

Upvotes: 1

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