Here is an interesting one. I found a way to take the %date% environment variable, and turn it into a valid string for a filename – without any extra programs or scripts.
For the longest time I used a little utility I created to do this. The problem with that is the utility needs to be around if you want to send the batch file to someone.
What I didn’t know that was that you can use this character combination ‘:~’ to pull a substring out of an environment variable. That is when I realized you could use this to pull out parts of the current date (or time).
Here is how it works. Lets take the %date% variable and print it out
echo %date%
It comes back …At least today 
.. with
Thu 02/15/2007
Not sure if the length of the day changes. It may be always the same. To be safe we can pull the year, month and day starting from the right.
The :~ substring command works like this:
:~[START POS],[LENGTH]
If [START_POS] is positive or zero the substring will start from the left. If the number [START_POS] is negative it will start from the right. And [LENGTH] is the number of characters in the opposite direction of the starting point.
I know this might be confusing at first, but you will see what I am talking about.
If we wanted to get the current year we could start 4 from the end, and 4 in length. Like this:
echo %date:~-4,4%
For the month we start 7 from the right (Length of Year + Length of Month + 1 Slash)
echo %date:~-7,2%
For the day we start 10 from the right (Length of Year + Length of Month + Length Of Day + 2 Slashes)
echo %date:~-10,2%
Bringing it all together. Lets say I zipped up a folder every night for archival purposes, and wanted a different filename for each day (Not sure if this pkzip syntax is correct, but that is not important for our discussion here)
pkzip c:\ImportantFolder\*.* c:\TempZip.zip
ren C:\TempZip.Zip c:\TempZip_%date:~-4,4%%date:~-7,2%%date:~-10,2%.zip
Which renames our C:\TempZip.Zip to C:\TempZip_20070215.zip
Perfect. I get a date stamped file, and no special vbscript, or command line program is needed.
The same method could be used for the current time
I am still amazed this little trick works.
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Great!!
Working Fine……..
here’s the “and time” bit:
I know it might sound obvious, but…
…….for time, use environment variable %time%
Good point. Title did not match my article. You can use the same principals with the time variable, and include hours, minutes, seconds, and milliseconds.
Here they are:
Milliseconds: %time:~-2,2%
Seconds: %time:~-5,2%
Minutes: %time:~-8,2%
Hours: %time:~-11,2%
Hi,
Thanks, These are very helpful tips.
The problen is that when retrieving the hour from the current time variable,
it appears with a leading space (instead of leading zero), when the hour is less than 10.
Any idea to solve it?
Lizzy
Here is the way to trim it:
SET HOUR=%time:~-11,2%
Call :TRIM %HOUR%
GOTO :EOF
:TRIM
Set HOUR=%*
:EOF
REM You would use your trimmed hour right here
@echo %HOUR%
fyi: the below line should be changed
from this: DATESTMP=%date:~-4,4%%date:~-7,2%%date:~-10,2%%HOUR% SET
swap 10,2 and 8,2 (date to be y/m/d)
insert :TRIM (else blank between hour and rest (m/s_DATA.ZIP)
to this: DATESTMP=%date:~-4,4%%date:~-10,2%%date:~-7,2%%HOUR% :TRIM SET
Great concept. thanks.
What format is your date in DD/MM/YYYY or MM/DD/YYYY…when you echo %date% at the command line?
Thanks.
Hi Guys,
i am newbie in the Batch file creation and hoping you guys can help and guide me on the following:-
i wanted to created a batch file to :-
1st – zip a folder containing a txt files
2nd – the batch file shall ignore the current date folder
3rd – the batch shall be executed on 1200am daily.
4th – the zipped folder name should retained
5th – once the folder has been zipped, it will be move to a dedicated folder (to another HDD or even to a network folder)
By the way, i am using power archiver 2001.
Thank you in advance..
bryan
@Lizzie – perhaps a little late but here’s how I ended up doing the leading space issue for the time
set tmp_time=%time:~-11,2%%time:~-8,2%%time:~-5,2%
:: method 1 use this to trim leading space entirely
::set tmp_time=%tmp_time: =%
:: method 2 use this to replace leading space with 0
set tmp_time=%tmp_time: =0%
@ Steve W. – Thanks!
Israel Torres