While loop in batch

Question

Here is what I want  inside the BACKUPDIR  I want to execute cscript  nologo c  deletefile vbs  BACKUPDIR  until number of files inside the folder is greater than 21 countfiles holds it   Here is my code    echo off SET BACKUPDIR C  test for  f   x in   dir  BACKUPDIR   b    find  v  c        do set countfiles   x  for  countfiles  GTR 21   cscript  nologo c  deletefile vbs  BACKUPDIR  set  a countfiles-  countfiles

User · Answer

A while loop can be simulated in cmd exe with    still more files     if  countfiles  leq 21           rem change countfile here         goto  still more files         For example  the following script        echo off     setlocal enableextensions enabledelayedexpansion     set  a  x   0    more to process     if  x  leq 5           echo  x          set  a  x   x   1          goto  more to process            endlocal   outputs   0 1 2 3 4 5   For your particular case  I would start with the following  Your initial description was a little confusing  I m assuming you want to delete files in that directory until there s 20 or less        echo off     set backupdir c  test   more files to process     for  f   x in   dir  backupdir   b    find  v  c        do set num   x     if  num  gtr 20           cscript  nologo c  deletefile vbs  backupdir          goto  more files to process

User · Answer

I have a trick for doing this  I came up with this method because while on the CLI  it s not possible to use the methods provided in the other answers here and it had always bugged me  I call this the  quot Do Until Break quot  or  quot Infinite quot  Loop  Basic Example FOR  L  L IN  0 0 1  DO     ECHO  Counter always 0  See  quot  L quot     quot 0 quot  - Waiting a split second amp ping -n 1 127 0 0 1 gt NUL     This is truly an infinite loop  This is useful for monitoring something in a CMD window  and allows you to use CTRL C to break it when you re done  Want to Have a counter  Either use SET  A OR You can modify the FOR  L Loop to do the counting and still be infinite  Note  BOTH of these methods have a 32bit integer overflow  SET  A Method  FOR  L  L IN  0 0 1  DO     SET  A  quot    1 quot  amp ECHO  L Still equals 0  See  quot  L   0 quot    - Waiting a split second  amp ping -n 1 127 0 0 1 gt NUL      Native FOR  L Counter  FOR  L  L IN  -2147483648 1 2147483648  DO     ECHO Current value of L   L - Waiting a split second  amp ping -n 1 127 0 0 1 gt NUL     Counting Sets of 4294967295 and Showing Current Value of L  FOR  L  L IN  1 1 2147483648  DO         IF  L EQU 0 SET  A  quot    1 quot  gt NUL    amp SET  A  quot    0 quot  amp ECHO  Sets of 4294967295 - Current value of L   L - Waiting a split second  amp ping -n 1 127 0 0 1 gt NUL    However  what if   You re interested in reviewing the output of the monitor  and concerned that I will pass the 9999 line buffer limit before I check it after it has completed  You d like to take some additional actions once the Thing I am monitoring is finished   For this  I determined how to use a couple methods to break the FOR Loop prematurely effectively turning it into a  quot DO WHILE quot  or  quot DO UNTIL quot  Loop  which is otherwise sorely lacking in CMD  NOTE   Most of the time a loop will continue to iterate past the condition you checked for  often this is a wanted behavior  but not in our case  Turn the  quot infinite Loop quot  into a  quot DO WHILE quot     quot DO UNTIL quot  Loop UPDATE  Due to wanting to use this code in CMD Scripts  and have them persist   as well as CLI  and on thinking if there might be a  quot more Correct quot  method to achieve this I recommend using the New method  New Method  Can be used inside CMD Scripts without exiting the script   FOR  F   A IN      CMD  C  quot FOR  L   L IN  0 1 2147483648  DO    ECHO   L  amp  IF  I   L EQU 10   exit  b      quot     DO      ECHO    A    At CLI  FOR  F  A IN      CMD  C  quot FOR  L  L IN  0 1 2147483648  DO    ECHO  L  amp  IF  I  L EQU 10   exit  b      quot     DO      ECHO   A    Original Method  Will work on CLI just fine  but will kill a script   FOR  L  L IN  0 1 2147483648  DO      ECHO Current value of L   L - Waiting a split second  amp ping -n 1 127 0 0 1 gt NUL amp       IF  I  L EQU 10         ECHO Breaking the Loop  Because We have matched the condition  amp DIR  gt  amp 0             2 gt NUL  Older Post Stuff Through chance I had hit upon some ways to exit loops prematurely that did not close the CMD prompt when trying to do other things which gave me this Idea  NOTE  While ECHO  gt  amp 3  gt NUL had worked for me in some scenarios  I have played with this off and on over the years and found that DIR  gt  amp 0  gt NUL was much more consistent  I am re-writing this answer from here forward to use that method instead as I recently found the old note to myself to use this method instead  Edited Post with better Method Follows  DIR  gt  amp 0  gt NUL  The  gt NUL is optional  I just prefer not to have it output the error  I prefer to match inLine when possible  as you can see in this sanitized example of a Command I use to monitor LUN Migrations on our VNX  for  l  L IN  0 0 1  DO       ECHO  amp  ECHO                                             amp          VNX CMD    FINDSTR  R  C  quot Source LU Name quot   C  quot State  quot   C  quot Time  quot     DIR  gt  amp 0  gt NUL       amp  Ping -n 10 1 1 1 1 -w 1000 gt NUL    Also  I have another method I found in that note to myself which I just re-tested to confirm works just as well at the CLI as the other method  Apparently  when I first posted here I posted an older iteration I was playing with instead of the two newer ones which work better  In this method  we use EXIT  B to exit the For Loop  but we don t want to exit the CLI so we wrap it in a CMD session  FOR  F  A IN   CMD  C  quot FOR  L  L IN  0 1 10000000  DO    ECHO  L  amp  IF  I  L EQU 10   exit  b      quot     DO   ECHO   A   Because the loop itself happens in the CMD session  we can use EXIT  B to exit the iteration of the loop without losing our CMD Session  and without waiting for the loop to complete  much the same as with the other method  I would go so far as to say that this method is likely the  quot intended quot  method for the sort of scenario where you want to break a for loop at the CLI  as using CMD session is also the only way to get Delayed expansion working at the CLI for your loops  and the behavior and such behavior is clearly an intended workflow to leave a CMD session  IE  Microsoft clearly made an intentional effort to have CMD Exit  B For loops behave this way  while the  quot Intended quot  way of doing this  as my other method  relies on having accidentally created just the right error to kick you out of the loop without letting the loop finish processing  which I only happenstantially discovered  and seems to only reliably work when using the DIR command which is fairly strange  So that said  I think it s probably a better practice to use Method 2  FOR  F  A IN   CMD  C  quot FOR  L  L IN  0 1 10000000  DO    ECHO  L  amp  IF  I  L EQU 10   exit  b      quot     DO   ECHO   A   Although I suspect Method 1 is going to be slightly faster  FOR  L  L IN  0 1 10000000  DO    ECHO  L  amp  IF  I  L EQU 10   DIR  gt  amp    gt NUL      And in either case  both should allow DO-While loops as you need for your purposes

User · Answer

It was very useful for me i have used in the following way to add user in active directory        This file is used to automatically add list of user to activedirectory    First ask for username pwd dc details and run in loop    dsadd user cn jai cn users dc mandrac dc com -pwd  1q 1q 1q 1q   echo off setlocal enableextensions enabledelayedexpansion set  a  x   1  set  p lent  Enter how many Users you want to create     set  p Uname  Enter the user name which will be rotated with number ex ram then ram1   etc     set  p DcName  Enter the DC name ex mandrac     set  p Paswd  Enter the password you want to give to all the users      cls   while1  if  x  leq  lent         dsadd user cn  Uname  x  cn users dc  DcName  dc com -pwd  Paswd      echo User  Uname  x  with DC  DcName  is created     set  a  x   x   1      goto  while1    endlocal

User · Answer

echo off  set countfiles 10   loop  set  a countfiles -  1  echo hi  if  countfiles  GTR 0 goto loop  pause   on the first  set countfiles  the 10 you see is the amount it will loop  the echo hi is the thing you want to loop      i m 5 years late

User · Answer

set  a countfiles-  countfiles    This will set countfiles to 0  I think you want to decrease it by 1  so use this instead   set  a countfiles- 1   I m not sure if the for loop will work  better try something like this    loop cscript  nologo c  deletefile vbs  BACKUPDIR  set  a countfiles- 1 if  countfiles  GTR 21 goto loop

[windows] While loop in batch

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