Source code for yesterday.bat

```
@IF /I NOT "%~1"=="/DEBUG" ECHO OFF
```
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:: Windows NT 4 or later only
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IF NOT "%OS%"=="Windows_NT" GOTO Syntax
```
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:: No command line arguments required
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IF NOT "%~1"=="" IF /I NOT "%~1"=="/DEBUG" GOTO Syntax

```
 
```
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:: Keep variables local
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SETLOCAL ENABLEDELAYEDEXPANSION
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```
 
```

:: Query the registry for the date format and delimiter

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CALL :DateFormat
```
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```

:: Parse today's date depending on registry's local date format settings

::IF %iDate%==0 FOR /F "TOKENS=1-4* DELIMS=%sDate%" %%A IN ('DATE/T') DO (

IF %iDate%==0 FOR /F "TOKENS=1-4* DELIMS=%sDate%" %%A IN ("%Date%") DO (

```
	SET LocalFormat=MM%sDate%DD%sDate%YYYY
```

	SET tLocal=%%tMonth%%%sDate%%%tDay%%%sDate%%%tYear%%

	SET yLocal=%%yMonth%%%sDate%%%yDay%%%sDate%%%yYear%%

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	SET Year=%%C
```
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	SET Month=%%A
```
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	SET Day=%%B
```
```
)
```

::IF %iDate%==1 FOR /F "TOKENS=1-4* DELIMS=%sDate%" %%A IN ('DATE/T') DO (

IF %iDate%==1 FOR /F "TOKENS=1-4* DELIMS=%sDate%" %%A IN ("%Date%") DO (

```
	SET LocalFormat=DD%sDate%MM%sDate%YYYY
```

	SET tLocal=%%tDay%%%sDate%%%tMonth%%%sDate%%%tYear%%

	SET yLocal=%%yDay%%%sDate%%%yMonth%%%sDate%%%yYear%%

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	SET Year=%%C
```
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	SET Month=%%B
```
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	SET Day=%%A
```
```
)
```

::IF %iDate%==2 FOR /F "TOKENS=1-4* DELIMS=%sDate%" %%A IN ('DATE/T') DO (

IF %iDate%==2 FOR /F "TOKENS=1-4* DELIMS=%sDate%" %%A IN ("%Date%") DO (

```
	SET LocalFormat=YYYY%sDate%MM%sDate%DD
```

	SET tLocal=%%tYear%%%sDate%%%tMonth%%%sDate%%%tDay%%

	SET yLocal=%%yYear%%%sDate%%%yMonth%%%sDate%%%yDay%%

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	SET Year=%%A
```
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	SET Month=%%B
```
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	SET Day=%%C
```
```
)
```
```
 
```
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:: Remove the day of week if applicable
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FOR %%A IN (%Year%)  DO SET Year=%%A
```
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FOR %%A IN (%Month%) DO SET Month=%%A
```
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FOR %%A IN (%Day%)   DO SET Day=%%A
```
```
 
```
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:: Today's date in YYYYMMDD format
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SET SortDate=%Year%%Month%%Day%
```
```
 
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:: Today's date in local format
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FOR %%A IN (%Date%) DO SET Today=%%A
```
```
 
```
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:: Remove leading zeroes
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IF   "%Day:~0,1%"=="0" SET   Day=%Day:~1%

IF "%Month:~0,1%"=="0" SET Month=%Month:~1%

```
 
```
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:: Calculate yesterday's date
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CALL :JDate %Year% %Month% %Day%
```
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SET /A JDate -= 1
```
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CALL :GDate %JDate%
```

FOR /F "tokens=1-3" %%A IN ('ECHO %GDate%') DO (

```
	SET yYear=%%A
```
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	SET yMonth=%%B
```
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	SET yDay=%%C
```
```
)
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:: Calculate tomorrow's date
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SET /A JDate += 2
```
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CALL :GDate %JDate%
```

FOR /F "tokens=1-3" %%A IN ('ECHO %GDate%') DO (

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	SET tYear=%%A
```
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	SET tMonth=%%B
```
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	SET tDay=%%C
```
```
)
```
```
 
```

:: Add leading zero to tDay, yDay, tMonth and/or yMonth if necessary

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IF 1%tDay%   LSS 20 SET tDay=0%tDay%
```
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IF 1%yDay%   LSS 20 SET yDay=0%yDay%
```

IF 1%tMonth% LSS 20 SET tMonth=0%tMonth%

IF 1%yMonth% LSS 20 SET yMonth=0%yMonth%

```
 
```

:: Yesterday's and tomorrow's date in YYYYMMDD format

```
SET SortTom=%tYear%%tMonth%%tDay%
```
```
SET SortYest=%yYear%%yMonth%%yDay%
```
```
 
```
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:: Display the results
```

ECHO Format:     YYYYMMDD  (%LocalFormat%)

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ECHO.==================================
```

CALL ECHO Yesterday:  %SortYest%  (%yLocal%)

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ECHO Today:      %SortDate%  (%Today%)
```

CALL ECHO Tomorrow:   %SortTom%  (%tLocal%)

```
 
```
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:: Done
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ENDLOCAL&SET Yesterday=%SortYest%&SET Today=%SortDate%&SET Tomorrow=%SortTom%

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GOTO:EOF
```
```
 
```

:: * * * * * * * *  Subroutines  * * * * * * * *

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```
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:DateFormat
```
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REG.EXE /? 2>&1 | FIND "REG QUERY" >NUL
```
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IF ERRORLEVEL 1 (
```
```
	CALL :DateFormatRegEdit
```
```
) ELSE (
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	CALL :DateFormatReg
```
```
)
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GOTO:EOF
```
```
 
```
```
 
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:DateFormatReg
```

FOR /F "tokens=1-3" %%A IN ('REG Query "HKCU\Control Panel\International" ^| FINDSTR /R /C:"[is]Date"') DO (

```
	IF "%%~A"=="REG_SZ" (
```
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		SET %%~B=%%~C
```
```
	) ELSE (
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		SET %%~A=%%~C
```
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	)
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```
)
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GOTO:EOF
```
```
 
```
```
 
```
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:DateFormatRegEdit
```

:: Export registry's date format settings to a temporary file, in case REG.EXE is not available

START /W REGEDIT /E %TEMP%.\_TEMP.REG "HKEY_CURRENT_USER\Control Panel\International"

```
:: Read the exported data
```

FOR /F "tokens=1* delims==" %%A IN ('TYPE %TEMP%.\_TEMP.REG ^| FIND /I "iDate"') DO SET iDate=%%B

FOR /F "tokens=1* delims==" %%A IN ('TYPE %TEMP%.\_TEMP.REG ^| FIND /I "sDate"') DO SET sDate=%%B

```
DEL %TEMP%.\_TEMP.REG
```
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:: Remove quotes from exported values
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SET iDate=%iDate:"=%
```
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SET sDate=%sDate:"=%
```
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GOTO:EOF
```
```
 
```
```
 
```
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:GDate
```

:: Convert Julian date back to "normal" Gregorian date

```
:: Argument : Julian date
```
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:: Returns  : YYYY MM DD
```
```
::
```

:: Algorithm based on Fliegel-Van Flandern

:: algorithm from the Astronomical Almanac,

:: provided by Doctor Fenton on the Math Forum

:: (http://mathforum.org/library/drmath/view/51907.html),

:: and converted to batch code by Ron Bakowski.

```
::
```
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SET /A P      = %1 + 68569
```
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SET /A Q      = 4 * %P% / 146097
```

SET /A R      = %P% - ( 146097 * %Q% +3 ) / 4

SET /A S      = 4000 * ( %R% + 1 ) / 1461001

SET /A T      = %R% - 1461 * %S% / 4 + 31

```
SET /A U      = 80 * %T% / 2447
```
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SET /A V      = %U% / 11
```

SET /A GYear  = 100 * ( %Q% - 49 ) + %S% + %V%

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SET /A GMonth = %U% + 2 - 12 * %V%
```
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SET /A GDay   = %T% - 2447 * %U% / 80
```
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:: Clean up the mess
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FOR %%A IN (P Q R S T U V) DO SET %%A=
```
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:: Add leading zeroes
```

IF 1%GMonth% LSS 20 SET GMonth=0%GMonth%

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IF 1%GDay%   LSS 20 SET GDay=0%GDay%
```
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:: Return value
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SET GDate=%GYear% %GMonth% %GDay%
```
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GOTO:EOF
```
```
 
```
```
 
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:JDate
```
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:: Convert date to Julian
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:: Arguments : YYYY MM DD
```
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:: Returns   : Julian date
```
```
::
```

:: Algorithm based on Fliegel-Van Flandern

:: algorithm from the Astronomical Almanac,

:: provided by Doctor Fenton on the Math Forum

:: (http://mathforum.org/library/drmath/view/51907.html),

:: and converted to batch code by Ron Bakowski.

```
::
```
```
SET /A Month1 = ( %2 - 14 ) / 12
```
```
SET /A Year1  = %1 + 4800
```

SET /A JDate  = 1461 * ( %Year1% + %Month1% ) / 4 + 367 * ( %2 - 2 -12 * %Month1% ) / 12 - ( 3 * ( ( %Year1% + %Month1% + 100 ) / 100 ) ) / 4 + %3 - 32075

```
FOR %%A IN (Month1 Year1) DO SET %%A=
```
```
GOTO:EOF
```
```
 
```
```
 
```
```
:UpCase
```
```
SET UpCase=%1
```
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SET UpCase=%UpCase:a=A%
```
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SET UpCase=%UpCase:b=B%
```
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SET UpCase=%UpCase:c=C%
```
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SET UpCase=%UpCase:d=D%
```
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SET UpCase=%UpCase:e=E%
```
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SET UpCase=%UpCase:f=F%
```
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SET UpCase=%UpCase:g=G%
```
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SET UpCase=%UpCase:h=H%
```
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SET UpCase=%UpCase:i=I%
```
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SET UpCase=%UpCase:j=J%
```
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SET UpCase=%UpCase:k=K%
```
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SET UpCase=%UpCase:l=L%
```
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SET UpCase=%UpCase:m=M%
```
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SET UpCase=%UpCase:n=N%
```
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SET UpCase=%UpCase:o=O%
```
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SET UpCase=%UpCase:p=P%
```
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SET UpCase=%UpCase:q=Q%
```
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SET UpCase=%UpCase:r=R%
```
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SET UpCase=%UpCase:s=S%
```
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SET UpCase=%UpCase:t=T%
```
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SET UpCase=%UpCase:u=U%
```
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SET UpCase=%UpCase:v=V%
```
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SET UpCase=%UpCase:w=W%
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SET UpCase=%UpCase:x=X%
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SET UpCase=%UpCase:y=Y%
```
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SET UpCase=%UpCase:z=Z%
```
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GOTO:EOF
```
```
 
```
```
 
```
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:Syntax
```
```
ECHO.
```

ECHO Yesterday.bat,  Version 3.11 for Windows NT and later

ECHO Display yesterday's, today's and tomorrow's dates in sorted and local format

```
ECHO.
```

IF     "%OS%"=="Windows_NT" CALL :UpCase %~n0

IF     "%OS%"=="Windows_NT" ECHO Usage:  %UpCase%  [ /DEBUG ]

IF NOT "%OS%"=="Windows_NT" ECHO Usage:  %0

```
ECHO.
```

ECHO Where:  /DEBUG    disables @ECHO OFF, thus displaying every command line

```
ECHO.
```

ECHO Notes:  Environment variables Yesterday, Today and Tomorrow are set to the

```
ECHO         sorted date values found.
```

ECHO         Adapted for Windows XP with help from Kailash Chanduka.

ECHO         Local date code by Frederic Guigand and Rob van der Woude.

ECHO         Julian date math algorithms based on Fliegel-Van Flandern algorithm

ECHO         from the Astronomical Almanac, provided by Doctor Fenton on the Math

ECHO         Forum (http://mathforum.org/library/drmath/view/51907.html), and

ECHO         converted to batch code by Ron Bakowski.

```
ECHO.
```
```
ECHO Written by Rob van der Woude
```
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ECHO http://www.robvanderwoude.com
```
```
 
```
```
IF "%OS%"=="Windows_NT" COLOR 00
```
```
 
```