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Microsoft => Microsoft DOS => Topic started by: Yogesh123 on September 24, 2009, 08:08:14 AM

Title: Batch How to handle multiple IF conditions
Post by: Yogesh123 on September 24, 2009, 08:08:14 AM

How to handle multiple IF conditions in a batch scripting
Ex:-
IF %Ti% EQU 2 (                       first if start
do this
do this
do this
do this
IF "%clc%" GEQ "800" set /a yy=%yy%+1
IF "%Day%" GTR "1" set /a yy=%yy%+1
IF %yy% LEQ 2 (
taskkill /F /IM calc.exe
) ELSE (
taskkill /F /IM notepad.exe
    )
) ELSE (                                      first if end
echo Bye Bye
    )

Thanks in advance

Title: Re: Batch How to handle multiple IF conditions
Post by: Salmon Trout on September 24, 2009, 10:43:38 AM

We do not know what your "do this" code does so cannot give detailed help. However, in a multi line IF structure, you need to use delayed expansion to set and read variables to work properly. You can Google for many pages about this.

Title: Re: Batch How to handle multiple IF conditions
Post by: Yogesh123 on September 25, 2009, 12:25:14 AM

Code: [Select]

[quote author=Salmon Trout link=topic=92501.msg625699#msg625699 date=1253810618]
We do not know what your "do this" code does so cannot give detailed help. However, in a multi line IF structure, you need to use delayed expansion to set and read variables to work properly. You can Google for many pages about this.


[/quote]
Dear Salmon Trout,
Pls find the code,
How to handle multiple IF conditions in a batch scripting
Ex:-

For /f "tokens=5" %%i in (6.txt) do set ci=%%i
IF %ci% EQU 2 ( [b] first if start[/b]
For /f "tokens=3" %%i in (6.txt) do set Tl=%%i
set Th=%Tl:~0,2%
set Tm=%Tl:~3,2%
Set TL=%Th%%Tm%
For /f "tokens=2" %%j in (4.txt) do set Tj=%%j
set /A Clc=%Tf%-%TL%
set /A Day=%dt%-%Tj%
:del 4.txt
echo %clc%
echo %Day%
set bool=0
[i]IF "%clc%" GEQ "800" set /a yy=%yy%+1
IF "%Day%" GTR "1" set /a yy=%yy%+1
IF %yy% LEQ 2 (
taskkill /F /IM calc.exe
) ELSE (
taskkill /F /IM notepad.exe
)
)[/i] ELSE ( [b]first if end[/b]
echo Bye Bye
)

Pls advice,
Thanks in advance

Title: Re: Batch How to handle multiple IF conditions
Post by: Salmon Trout on September 25, 2009, 12:58:05 AM

1. Normally, cmd.exe expands variables ONCE only, at parse time.
So with variables set and expanded inside parentheses e.g:

FOR bla bla ba (
    set var=abc
    echo %var%   
    )

or

IF bla bla bla (   
    set var=abc
    echo %var%   
    )

... the variable %var% is unknown at parse time, so is blank.
If it was set before the parentheses start, it retains that value.

Solution:
-- use delayed expansion, enable it at the start of the batch
-- use ! exclamation points instead of % percent signs for those
variables which are both set and expanded inside the parentheses.
(can use % signs to expand those variables after the parentheses end.)

REM Put this line near the start of the batch. Only need it once.
setlocal enabledelayedexpansion
FOR bla bla ba (
    set var=abc
    echo !var!   
    )

IF bla bla bla (
    set var=abc
    echo !var!
    )

2. Each IF can have only 1 ELSE. Therefore redesign logic.

e.g. use labels and goto

if "%animal%"=="CAT" goto meow
if "%animal%"=="DOG" goto grrrr
goto other

:meow
echo animal is a cat
goto next

:grrrr
echo animal is a dog
goto next

:other
echo animal is something else
goto next

:next
echo next part of code