A common question is how to give files names 
   based on date or time. This is most easily done 
   by placing the date and/or time in the environment 
   and working from there. If we had variables named 
   TIME and DATE, we could rename a generic file like 
   FILE.TXT to something like this:
   07-07-1998_4-56-13-83P-FILE.TXT
   with a line like this (assuming the file name is 
   being passed as %1):
   ren %1 "%date%_%time%-%1"

   Getting the date into the environment is easy. 
   Here's an example I call SETDATE.BAT:

----------------------------------------
@echo off
echo.|date|find "Current" >cu##ent.bat
echo set date=%%4> current.bat
call cu##ent.bat
del cu??ent.bat > nul
----------------------------------------

   Getting the time into the environment is just 
   as easy. Unfortunately, the time has embedded 
   colons in it, and colons aren't legal in file 
   names. Periods are legal, but they limit how 
   you can use the rename command. Removing 
   periods and colons is an character at a 
   time problem handled by misusing the 
   CHOICE command. Here's my suggestion 
   I call SETTIME.BAT for getting time 
   into the environment:

----------------------------------------
@echo off
echo.|time|find "Current" >cu##ent.bat
echo set time=%%3> current.bat
call cu##ent.bat
:: At this point the time is in the environment but has 
:: colons and periods in it. Both are bad news. They 
:: will be replaced by harmless dashes. CU??ENT.BAT 
:: are no longer needed and will be overwritten below
echo = | choice /c=%time%= cu##ent.bat > current.bat
echo @echo off> cu##ent.bat
echo set time=>> cu##ent.bat
echo :LOOP>> cu##ent.bat
echo shift>> cu##ent.bat
echo if "%%1"=="]?" goto DONE>> cu##ent.bat
echo if "%%1"==":" goto REPLACE>> cu##ent.bat
echo if "%%1"=="." goto REPLACE>> cu##ent.bat
echo goto KEEP>> cu##ent.bat
echo :REPLACE>> cu##ent.bat
echo set time=%%time%%->> cu##ent.bat
echo goto LOOP>> cu##ent.bat
echo :KEEP>> cu##ent.bat
echo set time=%%time%%%%1>> cu##ent.bat
echo goto LOOP>> cu##ent.bat
echo :DONE>> cu##ent.bat
call current.bat
del cu??ent.bat > nul
----------------------------------------

   Bad news if you live in the UK! The date
   command there includes slashes which aren't 
   allowed in file names. What's worse, the 
   method I use (using the CHOICE command) to 
   remove colons from the TIME output won't 
   work: CHOICE can't handle slashes. So here 
   is SETDATE.BAT which will work in the US or 
   UK, but insures the date separator is a dash:

----------------------------------------
@echo off
echo.|date|find "Current" >cu##ent.bat
echo set date=%%4> current.bat
:: At this point cu##ent.bat contains a line like
:: Current date is Wed 10-06-1999
:: in the US or
:: Current date is Wed 06/10/1999
:: in the UK. But we must remove UK slashes! They
:: always occur in the same place, so we use DEBUG 
:: to ensure they are harmless US style dashes.
echo e 116 "-" > script
echo e 119 "-" >> script
echo w >> script
echo q >> script
type script | debug cu##ent.bat > nul
del script > nul
call cu##ent.bat
----------------------------------------

   So as a final example, assume I have a program 
   named PROCESS.BAT which produces a file named 
   FILE.TXT. I run the PROCESS program several 
   times a day, but each run overwrites the old 
   FILE.TXT. To save the file, I must rename it 
   with a unique name. I can do this by adding 
   date and time to the filename:

----------------------------------------
call process.bat
call setdate.bat
call settime.bat
ren file.txt "%date%_%time%-file.txt"
set time=
set date=
----------------------------------------

   Now instead of running my PROCESS.BAT, I run 
   the code shown above. Notice I use dashes to 
   separate the time, date, and file name. Even 
   though there are no spaces in the example I 
   used, I still put quotes around the name. I 
   shouldn't have to, but sometimes the REN 
   command can be picky. Always quote file names 
   to be on the safe side!

   CAUTION: All the above code (like 
   virtually all my code) is for Win9x. 
   If you use NT, please go to this page:
   http://www.calweb.com/~webspace/batch/nt/index.htm
   and look for the links telling you how 
   to set the date into the environment. 
   Alternatively, if you installed scripting 
   (it came out with NT SP4), go to this page:
   http://www.calweb.com/~webspace/scripting/index.htm
   and look for the links to "DateName.vbs" 
   and "TimeDateName.vbs" near the bottom of the page.

   http://www.calweb.com/~webspace