How to increment variable under DOS?

Question

I\'ve spent the past 3hrs trying to work this out but just couldn\'t find a solution. Here\'s my batch script:

if NOT Exist Counter.txt GOTO START
Type c:\\count         


        

Answer 1

I didn't use DOS for - puh - feels like decades, but based on an old answer and my memories, the following should work (although I got no feedback, the answer was accepted, so it seems to work):

@echo off
  REM init.txt should already exist
  REM to create it:
  REM   COPY CON INIT.TXT
  REM   SET VARIABLE=^Z
  REM ( press Ctrl-Z to generate ^Z )
  REM
  REM also the file "temp.txt" should exist.
REM add another "x" to a file:
echo x>>count.txt
REM count the lines in the file and put it in a tempfile:
type count.txt|find /v /c "" >temp.txt

REM join init.txt and temp.txt to varset.bat:
copy init.txt+temp.txt varset.bat
REM execute it to set %variable%:
call varset.bat

for %%i in (%variable%) do set numb=%%i
echo Count is: %numb%
   REM just because I'm curious, does the following work? :
   set numb2=%variable%
   echo numb2 is now %var2%
if %numb%==250 goto :finished
echo another boot...
warmboot.exe
:finished
echo that was the last one.

In DOS, neither set /a nor set /p exist, so we have to work around that. I think both for %%i in (%variable%) do set numb=%%i and set numb2=%variable% will work, but I can't verify.

WARNING: as there is no ">" or "<" comparison in DOS, you should delete the batchfile at the :finished label (because it continues to increment and 251 is not equal 250 anymore)

(PS: the basic idea is from here. Thanks foxidrive. I knew, I knew it from StackOverflow but had a hard time to find it again)