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Batch script loop

I need to execute a command 100-200 times, and so far my research indicates that I would either have to copy/paste 100 copies of this command, OR use a for loop, but the for loop expects a list of items, hence I would need 200 files to operate on, or a list of 200 items, defeating the point.

I would rather not have to write a C program and go through the length of documenting why I had to write another program to execute my program for test purposes. Modification of my program itself is also not an option.

So, given a command, a, how would I execute it N times via a batch script?

Note: I don't want an infinite loop

For example, here is what it would look like in Javascript:

var i;
for (i = 0; i < 100; i++) {
  console.log( i );
} 

What would it look like in a batch script running on Windows?


T
Top-Master

for /l is your friend:

for /l %x in (1, 1, 100) do echo %x

Starts at 1, steps by one, and finishes at 100.

WARNING: Use %% instead of %, if it's in a batch file, like:

for /l %%x in (1, 1, 100) do echo %%x

(which is one of the things I really really hate about windows scripting.)

If you have multiple commands for each iteration of the loop, do this:

for /l %x in (1, 1, 100) do (
   echo %x
   copy %x.txt z:\whatever\etc
)

or in a batch file

for /l %%x in (1, 1, 100) do (
   echo %%x
   copy %%x.txt z:\whatever\etc
)

Key:
/l denotes that the for command will operate in a numerical fashion, rather than operating on a set of files
%x is the loops variable
(starting value, increment of value, end condition[inclusive] )


That depends on how literally we are to take the "DOS" reference. The latest version of MS-DOS, 7.1, dates back to 1997 and AFAIK doesn't have these extensions. The command shells delivered with Windows, on the other hand, of course do.
@Imray %x is the loop variable, /l (not \l) means that the for command will operate in a numerical fashion, rather than operating on a set of files.
By running for /l %x in (1, 1, 100) do echo %x i get "x not expected".
@user193655 read the rest of the answer, you need to double the %s if you're doing this in a batch file.
@Jon, Why is it that two % is required if using a batch file?
O
Olivier Faucheux

And to iterate on the files of a directory:

@echo off 
setlocal enableDelayedExpansion 

set MYDIR=C:\something
for /F %%x in ('dir /B/D %MYDIR%') do (
  set FILENAME=%MYDIR%\%%x\log\IL_ERROR.log
  echo ===========================  Search in !FILENAME! ===========================
  c:\utils\grep motiv !FILENAME!
)

You must use "enableDelayedExpansion" and !FILENAME! instead of $FILENAME$. In the second case, DOS will interpret the variable only once (before it enters the loop) and not each time the program loops.


Thanks for posting this -- I know it's not what the OP was asking, but it's what I was searching for when I ended up here.
F
FluorescentGreen5

Template for a simple but counted loop:

set loopcount=[Number of times]
:loop
[Commands you want to repeat]
set /a loopcount=loopcount-1
if %loopcount%==0 goto exitloop
goto loop
:exitloop

Example: Say "Hello World!" 5 times:

@echo off
set loopcount=5
:loop
echo Hello World!
set /a loopcount=loopcount-1
if %loopcount%==0 goto exitloop
goto loop
:exitloop
pause

This example will output:

Hello World!
Hello World!
Hello World!
Hello World!
Hello World!
Press any key to continue . . .

this is the only loop code i was able to use on my win7 pc. All the others found by googleing do not work.
In your example, I would add set /p loopcount="How many loops? " so that you can run it with user input. It's more practical.
P
Peter Mortensen

You could also try this instead of a for loop:

set count=0
:loop
set /a count=%count%+1
(Commands here)
if %count% neq 100 goto loop
(Commands after loop)

It's quite small and it's what I use all the time.


This is basically identical to Marcus Culver's answer. Please do not post answers that do not add anything new. Thank you!
Ups sry did not see that, just flew threw it and just saw for loops... Im sorry then :)
M
Marcus Culver

You could do something to the following effect avoiding the FOR loop.

set counter=0
:loop
echo "input commands here"
SET /A counter=%counter%+1
if %counter% GTR 200
(GOTO exit) else (GOTO loop)
:exit
exit

P
Peter Mortensen

Or you can decrement/increment a variable by the number of times you want to loop:

SETLOCAL ENABLEDELAYEDEXPANSION
SET counter=200
:Beginning
IF %counter% NEQ 0 (
echo %x
copy %x.txt z:\whatever\etc
SET /A counter=%counter%-1
GOTO Beginning
) ELSE (
ENDLOCAL
SET counter=
GOTO:eof

Obviously, using FOR /L is the highway and this is the backstreet that takes longer, but it gets to the same destination.


R
Rakesh Chaudhari

Very basic way to implement looping in cmd programming using labels

@echo off
SET /A "index=1"
SET /A "count=5"
:while
if %index% leq %count% (
   echo The value of index is %index%
   SET /A "index=index + 1"
   goto :while
)

P
Peter Mortensen

You can do this without a for statement ^.^:

@echo off
:SPINNER
SET COUNTP1=1

:1
CLS
 :: YOUR COMMAND GOES HERE
IF !COUNTP1! EQU 200 goto 2

SET COUNTP1=1
) ELSE (
SET /A COUNTP1+=1
)
goto 1

:2
:: COMMAND HAS FINISHED RUNNING 200 TIMES

It has basic understanding. Just give it a test. :P


you don't need delayed expansion here.
C
Carl Smotricz

DOS doesn't offer very elegant mechanisms for this, but I think you can still code a loop for 100 or 200 iterations with reasonable effort. While there's not a numeric for loop, you can use a character string as a "loop variable."

Code the loop using GOTO, and for each iteration use SET X=%X%@ to add yet another @ sign to an environment variable X; and to exit the loop, compare the value of X with a string of 100 (or 200) @ signs.

I never said this was elegant, but it should work!


The /a option of the SET command will evaluate a numerical expression for the right side value. See the doucmentation for SET. It is not necessary to do the concatenation trick.
for DOS, it is neccessary, as there is no set /a in DOS. Luckily the qeustion is for cmd... (at the time of this answer, the question title was "DOS batch script loop"
J
Josh Girouard

Not sure if an answer like this has already been submitted yet, but you could try something like this:

@echo off
:start
set /a var+=1
if %var% EQU 100 goto end
:: Code you want to run goes here
goto start

:end
echo var has reached %var%.
pause
exit

The variable %var% will increase by one until it reaches 100 where the program then outputs that it has finished executing. Again, not sure if this has been submitted or something like it, but I think it may be the most compact.


J
Jordan B

I use this. It is just about the same thing as the others, but it is just another way to write it.

@ECHO off
set count=0
:Loop
if %count%==[how many times to loop] goto end
::[Commands to execute here]
set count=%count%+1
goto Loop
:end

D
Dr. Hugh Jarse

The answer really depends on how familiar you are with batch, if you are not so experienced, I would recommend incrementing a loop variable:

@echo off
set /a loop=1
:repeat
echo Hello World!
set /a loop=%loop%+1
if %loop%==<no. of times to repeat> (
goto escapedfromrepeat
)
goto repeat
:escapedfromrepeat
echo You have come out of the loop
pause

But if you are more experienced with batch, I would recommend the more practical for /l %loop in (1, 1, 10) do echo %loop is the better choice.

             (start at 1, go up in 1's, end at 10)
for /l %[your choice] (start, step, end) do [command of your choice]

g
guest257351

a completely flawless loop

set num=0
:loop
:: insert code
set /a num=%num%+1
if %num% neq 10 goto loop
::insert after code code

you can edit it by changing the 10 in line 5 to any number to represent how many time you want it to loop.


This will not work unless you specify /a parameter in the second set command like this: set /a num=%num%+1. Without this, it's not performing arithmetic operation, but just adding "+1" as a string to the original value and you end up with "0+1+1+1+1+1..." string at the end.
thanks, I forgot about that, my bad. Started using python and got used to not needing different paramaters.
H
Hamed

Use FOR /l and make sure to use %% instead of % It will save you headaches.

And try to Set the loop.


Thank you for your participation, but this answer doesn't add any useful information to the twelve years old accepted answer, and so just adds noise and likely attracts downvotes and closure/deletion requests.
M
Manny

(EDITED) I made it so it stops after 100 times

@echo off
goto actual
set /a loopcount=0
:actual
set /a loopcount=%loopcount% + 1
echo %random% %random% %random% %random%
timeout 1 /nobreak>nul
if %loopcount%== 100 goto stop
goto actual
:stop
exit

This will generate 4 random numbers ever 1 second 100 times. Take out the "timeout 1 /nobreak>nul" to make it go super fast.


the question was "100 - 200 times", not "endless loop".
C
Cocos Nucifera

I have 2 answers Methods 1: Insert Javascript into Batch

@if (@a==@b) @end /*

:: batch portion

@ECHO OFF

cscript /e:jscript "%~f0"


:: JScript portion */

Input Javascript here

( I don't know much about JavaScript )

Method 2: Loop in Batch

   @echo off
    set loopcount=5
    :loop
    echo Hello World!
    set /a loopcount=loopcount-1
    if %loopcount%==0 goto exitloop
    goto loop
    :exitloop
    pause

(Thanks FluorescentGreen5)


We appreciate your attempt to contribute, but repeating a five year old answer verbatim doesn't help much and just adds noise.