Get Yesterday’s date in MS DOS Batch file

Posted in amazon s3 log analysis, AWS, Batch File, Command Line, S3

A while back while I was trying to figure out the best way to gather some log files from Amazon S3 buckets and some web servers I run.  These resources are currently generating around 10-15GB of uncompressed log files daily.  Besides being fairly large in size the S3 (and CloudFront) log files are numerous.  Any given bucket can easily generate 1,000 or more log files per day – that’s a whole other story. . .

Anyway, I wanted to be able to run a process sometime after midnight that would gather and zip the previous day’s files and stash the zipped files in another location for archival.  It’s pretty easy to calculate the previous day’s date if it’s in the middle of the month, but what if it’s the first of the month, first of the year, and what about leap year, etc., etc. . . ?  So I searched around the web a bit and came across a great solution to this issue on Experts Exchange (Get Yesterday date in MS DOS Batch file).  Thanks to SteveGTR for this one.
I have modified the original script a bit to suite my needs.  Most notably at the end of the script I create two variables, IISDT and AWSDT, to match IIS and Amazon Web Services (S3 and CloudFront) log formats, respectively.  I use this in a simple batch file which is executed like, “gather_log_files.bat 1.”  The number “1” is passed into the script which calculates the date of “1” day before the current date.  Of course you could pass any number in there to generate a date x days in the past.  It’s very slick. NOTE: If you don’t specify a number after the batch file “1” is assumed.
So, without further ado, here’s the script.

@echo off

set yyyy=

set $tok=1-3
for /f “tokens=1 delims=.:/-, ” %%u in (‘date /t’) do set $d1=%%u
if “%$d1:~0,1%” GTR “9” set $tok=2-4
for /f “tokens=%$tok% delims=.:/-, ” %%u in (‘date /t’) do (
for /f “skip=1 tokens=2-4 delims=/-,().” %%x in (‘echo.^|date’) do (
set %%x=%%u
set %%y=%%v
set %%z=%%w
set $d1=
set $tok=))

if “%yyyy%”==”” set yyyy=%yy%
if /I %yyyy% LSS 100 set /A yyyy=2000 + 1%yyyy% – 100

set CurDate=%mm%/%dd%/%yyyy%
set dayCnt=%1

if “%dayCnt%”==”” set dayCnt=1

REM Substract your days here
set /A dd=1%dd% – 100 – %dayCnt%
set /A mm=1%mm% – 100

:CHKDAY
if /I %dd% GTR 0 goto DONE
set /A mm=%mm% – 1
if /I %mm% GTR 0 goto ADJUSTDAY
set /A mm=12
set /A yyyy=%yyyy% – 1

:ADJUSTDAY
if %mm%==1 goto SET31
if %mm%==2 goto LEAPCHK
if %mm%==3 goto SET31
if %mm%==4 goto SET30
if %mm%==5 goto SET31
if %mm%==6 goto SET30
if %mm%==7 goto SET31
if %mm%==8 goto SET31
if %mm%==9 goto SET30
if %mm%==10 goto SET31
if %mm%==11 goto SET30
REM ** Month 12 falls through

:SET31
set /A dd=31 + %dd%
goto CHKDAY

:SET30
set /A dd=30 + %dd%
goto CHKDAY

:LEAPCHK
set /A tt=%yyyy% %% 4
if not %tt%==0 goto SET28
set /A tt=%yyyy% %% 100
if not %tt%==0 goto SET29
set /A tt=%yyyy% %% 400
if %tt%==0 goto SET29

:SET28
set /A dd=28 + %dd%
goto CHKDAY

:SET29
set /A dd=29 + %dd%
goto CHKDAY

:DONE
if /I %mm% LSS 10 set mm=0%mm%
if /I %dd% LSS 10 set dd=0%dd%

REM Set IIS and AWS date variables
set IISDT=%yyyy:~2,2%%mm%%dd%
set AWSDT=%yyyy%-%mm%-%dd%

The results would look like:

IIS Date: 20100727

AWS Date: 2010-07-27

Posted on By user

35 thoughts on “Get Yesterday’s date in MS DOS Batch file”

  4. This is the best way I've found to get yesterday's date in a dos or windows command line or batch file. Great work!!

    Reply

  13. This is indeed good, I use it to move the previous days log file to a folder. The only problem is, it doesn't work for moving Friday's log file on Monday. Any way it could be modified to get the previous business days date.

    Reply

  19. Any idea how this can be amended if I want to find files and copy to folders with this date format:
    DD-MMM-YYYY, e.g
    21-NOV-2012

    Reply

  25. I'm pretty new to .bat files. I understand that this is supposed to retrieve the previous day's date, but how can I check it to make sure? As soon as I run the .bat file, it closes. Please be gentle lol.

    Reply

  26. You could add any (or all) of the following to the bottom of the batch file, including "pause." That way it will display the value(s) on screen, then pause the execution of the file.

    echo %IISDT%
    echo %AWSDT%
    pause

    Reply

  29. Unlike all other scripts that are either uncomplete, confusing, show-off or incorrect, this one really gets to the point and works. many thanks!

    Reply

  31. this is great. if you want it to go back to last working day (ie 3 days on Monday) add this at the top
    for /f "skip=1 tokens=1" %%a in ('wmic path win32_localtime get dayofweek ^| findstr /b /r "."') do set /a dow=%%a +1
    for /f "tokens=%dow%" %%a in ("Sunday Monday Tuesday Wednesday Thursday Friday Saturday") do set day=%%a
    echo Today is %dow% which is %day%

    echo if it's Monday we go back 3 days for the filename (friday), otherwise it's just one day
    set dayCnt=1
    if "%dow%"=="2" set dayCnt=3
    echo going back %dayCnt% days

    Reply

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