Need a Server? Build it in the cloud for free


How to Create FileName Variable with Date And Time From Command CMD Batch File For Use in Creating Unique Filename

I created this script for use in my AutoBootVHD8.cmd file which is part of a hands on lab

Here is the resulting code.. 

@echo Backing up Boot Configuration Data
Rem Create FileName with datatime
:: this is Regional settings dependent so tweak this according your current settings
Echo %DATE% %Time%
for /f “tokens=1-8 delims=::./ ” %%A in (‘echo %DATE% %TIME%’) do set  FileDateTime=%%D%%C%%B-%%E%%F%%G
ECHO FileDateTime IS %FileDateTime%
@echo  %temp%\AutoBootBackup-%filedatetime%.bak
Echo This is a test file > %temp%\AutoBootBackupTemp-%FileDateTime%.bak
BCDEDIT /export %temp%\AutoBootBackup-%FileDateTime%.bak
dir %temp%\AutoBootBackup*


Now, I will explain what each line does

Command Description
@echo Backing up Boot Configuration Data Display a comment on the screen so the user knows what we are doing
Rem Create FileName with datatime Code comment that just tells other programmers that are looking at the code what we are doing.
:: this is Regional settings dependent so tweak this according your current settings Another comment, just a note to programmers
Echo %DATE% %Time% This is used to DISPLAY the contents of what we will be parsing.  You do not need to leave it in the code.  I left it in so you could easily tweak for different regional settings or rearranging the values.
The output of this is used to figure out what the different parts are in our loop
Output: Thu 02/07/2013 10:53:06.12
for /f “tokens=1-8 delims=::./ ” %%A in (‘echo %DATE% %TIME%’) do set  FileDateTime=%%D%%C%%B-%%E%%F%%G This is where all the real work is done.  We are looping through the output of the “%DATE% %Time%” output and breaking it down into different parts (called tokens). 

in (‘echo %DATE% %TIME%’) tells the script to process the results of this statement for the text we are going to scan through.  The output can be seen above.

Tokens are defined by “tokens=1-8 delims=::./ “  1-8 says return only the first through the 8th tokens.  A token is a Part.  tokens are defined by a character which is defined by the %%A which says starting with “A” return each token in the next ASCII character.  So A=Token1, B=Token2, C=Token3, etc all the way up to the max tokens which in this statement is 8 (remember 1-8 tokens)

In this case, we are using several “delims” (delimiters). 

delims are defined by delims=::./ “
in this case, we are using multiple delims: 
colon(::),  {colon is a special reserved character so we have to double it}
forward slash (/),
space ( )

Anytime one of these characters is found in the string we are processing a new token will be created from the text “Thu 02/07/2013 10:53:06.12”
The tokens and delims work together to break down the text as follows
Token1=A  Token2=B  / T3=C   / T4=D       T5=E   : T6=F    : T7=G    .T8= H
 Thu             02               / 07        /  2013       10       : 53         : 06        .12

After the tokens are broken up they are stored in variables %%A through %%H

So the last thing we have to do is create a new variable that uses our tokens to create the FileDateTime variable.  This is done with the part of the statement “do set  FileDateTime=%%D%%C%%B-%%E%%F%%G”

In my case, I am not using the %%H variable and I rearranged the date tokens so it would display YYYYMMDD followed by the time HHMMSS and I store that into a new variable called FileDateTime

ECHO FileDateTime IS %FileDateTime% display the contents of our new variable FileDateTime

Output: FileDateTime IS 20130702-105306

@echo  %temp%\AutoBootBackup-%filedatetime%.bak Now use this FileDateTime variable to display what we will be using for our actual filename. 
The %temp% is a variable that is the location of Temporary files

Output:  C:\Users\DSTOLT~1.NOR\AppData\Local\Temp\AutoBootBackup-20130702-105306.bak

Echo This is a test file > %temp%\AutoBootBackupTemp-%FileDateTime%.bak This command just creates a temporary text file using the temp variable and the FileDateTime variable with a .bak extention.  The contents of the text file is “This is a test file” and the name of the file is:


BCDEDIT /export %temp%\AutoBootBackup-%FileDateTime%.bak You can delete this line.  This is how I will ultimately be using the command.  I am passing the output filename to the BCDEDIT /Export function. 
dir %temp%\AutoBootBackup* I am just showing  a listing of the files in my temp folder that start with “AutoBootBackup” so I can see that the file was successfully created.

Please NOTE:  The only line you really need is the “for /f “tokens=1-8 delims=::./ ” %%A in (‘echo %DATE% %TIME%’) do set  FileDateTime=%%D%%C%%B-%%E%%F%%G”  This will set an environment variable for FileDateTime then you can use that however you like.  All the other lines in the script are simply provided to show you examples of how you can use this technology.


output from running the script on my computer:


Backing up Boot Configuration Data

C:\Boot>Rem Create FileName with datatime

C:\Boot>Echo Thu 02/07/2013 10:53:06.12
Thu 02/07/2013 10:53:06.12

C:\Boot>for /F “tokens=1-8 delims=::./ ” %A in (‘echo Thu 02/07/2013 10:53:06.12
‘) do set  FileDateTime=%D%C%B-%E%F%G

C:\Boot>set  FileDateTime=20130702-105306

C:\Boot>ECHO FileDateTime IS 20130702-105306
FileDateTime IS 20130702-105306


C:\Boot>Echo This is a test file  1>C:\Users\DSTOLT~1.NOR\AppData\Local\Temp\AutoBootBackupTemp-20130702-105306.bak

C:\Boot>BCDEDIT /export C:\Users\DSTOLT~1.NOR\AppData\Local\Temp\AutoBootBackup-20130702-105306.bak
The operation completed successfully.

C:\Boot>dir C:\Users\DSTOLT~1.NOR\AppData\Local\Temp\AutoBootBackup*
Volume in drive C is OSDisk
Volume Serial Number is FE20-0485

Directory of C:\Users\DSTOLT~1.NOR\AppData\Local\Temp

02/07/2013  10:28 AM            65,536 AutoBootBackup-20130702-102855.bak
02/07/2013  10:29 AM            65,536 AutoBootBackup-20130702-102905.bak
02/07/2013  10:47 AM            65,536 AutoBootBackup-20130702-104709.bak
02/07/2013  10:53 AM            65,536 AutoBootBackup-20130702-105306.bak
02/07/2013  10:47 AM            65,536 AutoBootBackup.bak
02/07/2013  10:47 AM                22 AutoBootBackupTemp-20130702-104709.bak
02/07/2013  10:53 AM                22 AutoBootBackupTemp-20130702-105306.bak
               7 File(s)        327,724 bytes
               0 Dir(s)  174,626,017,280 bytes free



I do hope you found this helpful.  If you did, send me a thank you note with the URL on Twitter @ITProGuru

You can use only the date or only the time by just deleting the parts you do not want from the

do set  FileDateTime=%%D%%C%%B-%%E%%F%%G
part of the command




- = Static text




%%H=hundreds of seconds which I did not use

%%A= Day of week which I did not use



If I add another command to the top of the script (@Echo Off) I would get the following (clean) output


This entry was posted in Step-By-Step and tagged , , by Dan Stolts ITProGuru. Bookmark the permalink.

About Dan Stolts ITProGuru

Dan Stolts (The "ITProGuru") is a technology expert who is a master of systems management and security. He is proficient in many Microsoft products especially in the server area (Windows Server, System Center, Exchange, SharePoint, Virtualization, Etc) and holds many certifications including MCT, MCITP, MCSE, TS, etc. Dan is currently specializing in System Management and Security and is also very passionate about virtualization technologies. Dan is and has been a very active member of the community. He is president of Boston User Groups, Founder of Virtualization Group Boston, Founder of North East Leaders and serves on many IT Community group boards. He is in the process of writing his first book on building technology communities. He is a believer in social networking and can be reached on twitter @ITProGuru. He has participated in many non-technology community groups such as: Rotary Club, Lions Club, local Chambers of Commerce and is a mentor for the local high schools. Dan is an enthusiastic advocate of technology and is passionate about helping others. Dan's lifelong passion has been and continues to be to help and teach others!

Leave a Reply