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  counter txt if  COUNTER  EQU  Cycles  goto Pass if NOT  COUNTER  EQU  Cycles  goto Cycle   START Set COUNTER 0 set CYCLES 250   Cycle set  A COUNTER  COUNTER  1      lt ----------- PROBLEM echo Iteration  COUNTER  of  CYCLES  echo Delay 3 seconds to reboot choice  cy  n  t y 3 warmboot com   Pass pause   What it s doing is it runs the file  warmboot com   which reboots my PC  and runs for 250 cycles  Once the cycles have run 250 times  i e when counter equals cycles  then it stops   Under Windows  this works  However  this doesn t work under DOS environment  I ve tried versions from v4 all the way up to v6 22 and even v7 and they all fail when it reaches the  PROBLEM  line   If I do this   set  A COUNTER  COUNTER  1 echo  Counter    OR this   set  A COUNTER  1 echo  Counter    both will return a blank line  i e it shows nothing as the output    If I type   set      then it shows this      Displays  sets  or removes cmd exe environment variables       SET  variable  string        variable  Specifies the environment-variable name      string   Specifies a series of characters to assign to the variable    but typing the same command under CMD in Windows shows a lot more stuff  I m thinking that the SET function under DOS doesn t support arithmetic functions  but for work purposes I have to run my scripts in DOS only   Any ideas

User · Answer

Coming to the party very very late  but from my old memory of DOS batch files  you can keep adding a character to the string each loop then look for a string of that many of that character   for 250 iterations  you either have a very long  cycles  string  or you have one loop inside using one set of variables counting to 10  then another loop outside that uses another set of variable counting to 25   Here is the basic loop to 30    echo off rem put how many dots you want to loop set cycles                                set cntr   LOOP set cntr  cntr   echo around we go again if   cycles      cntr   goto done goto loop  DONE echo around we went

User · Answer

I built my answer thanks to previous contributors   Not having time for a custom counter exe  I downloaded sed for FREEDOS   And then the batch code could be  emulating  wc -l  with the utility sed  something like this according to your loop  I just use it to increment through executions starting from  1  to n 1    Just remember to manually create a file  test txt  with written on the first row     0     sed -n      test txt  gt  counter txt set  P Var  lt  counter txt echo 0  gt  gt  test txt

User · Answer

None of these seemed to work for me   ECHO OFF  REM 1  Initialize our counter SET  A  quot c 0 quot   REM Iterate through a dummy list   REM Notice how the counter is used   quot CALL ECHO   c   quot   FOR  L   i in  10 1 20  DO      REM 2  Increment counter   SET  A  quot c  1 quot     REM 3  Print our counter  quot  c  quot  and some dummy data  quot   i quot    CALL ECHO Line   c    - Data    i    The answer was extracted from  https   www tutorialspoint com batch script batch script arrays htm  Section  Length of an Array  Result  Line 1  - Data  10 Line 2  - Data  11 Line 3  - Data  12 Line 4  - Data  13 Line 5  - Data  14 Line 6  - Data  15 Line 7  - Data  16 Line 8  - Data  17 Line 9  - Data  18 Line 10  - Data  19 Line 11  - Data  20

User · Answer

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 gt  gt count txt REM count the lines in the file and put it in a tempfile  type count txt find  v  c     gt 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   lt   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

User · Answer

I realize you ve found another answer - but the fact is that your original code was nearly correct but for a syntax error   Your code contained the line  set  A COUNTER  COUNTER  1   and the syntax that would work is simply     set  A COUNTER COUNTER 1   See http   ss64 com nt set html for all the details on the SET command  I just thought I d add this clarification for anyone else who doesn t have the option of using FreeDOS

User · Answer

Directly from the command line    for  L  n in  1 1 100  do  echo  n   Using a batch file     echo off  for  L   n in  1 1 100  do echo   n   Displays    1  2  3       100

User · Answer

A little bit late for the party  but it s an interessting question   You can write your own inc bat for incrementing a number  It can increment numbers from 0 to 9998      echo off if   1     inc  goto  increment  call  0  inc  counter0  set counter0   cnt  if   overflow   0 goto  exit   call  0  inc  counter1  set counter1   cnt  if   overflow   0 goto  exit   call  0  inc  counter2  set counter2   cnt  if   overflow   0 goto  exit   call  0  inc  counter3  set counter3   cnt  goto  exit   increment set  overflow 0 set  cnt  2  if    cnt       set  cnt 0  if   cnt   9 goto  overflow if   cnt   8 set  cnt 9 if   cnt   7 set  cnt 8 if   cnt   6 set  cnt 7 if   cnt   5 set  cnt 6 if   cnt   4 set  cnt 5 if   cnt   3 set  cnt 4 if   cnt   2 set  cnt 3 if   cnt   1 set  cnt 2 if   cnt   0 set  cnt 1 goto  exit   overflow set  cnt 0 set  overflow 1 goto  exit   exit set count  counter3  counter2  counter1  counter0    A sample for using it is here   echo off set counter0 0 set counter1  set counter2  set counter3    loop call inc bat echo  count  if not  count   250 goto  loop

User · Answer

Indeed  set in DOS has no option to allow for arithmetic  You could do a giant lookup table  though   if  COUNTER   249 set COUNTER 250     if  COUNTER   3 set COUNTER 4 if  COUNTER   2 set COUNTER 3 if  COUNTER   1 set COUNTER 2 if  COUNTER   0 set COUNTER 1

User · Answer

I ve found my own solution   Download FreeDOS from here  http   chtaube eu computers freedos bootable-usb   Then using my Counter exe file  which basically generates a Counter txt file and increments the number inside every time it s being called   I can assign the value of the number to a variable using   Set  P Variable   lt  Counter txt   Then  I can check if it has run 250 cycles by doing   if  variable   250 echo PASS   BTW  I still can t use Set  A since FreeDOS doesn t support this command  but at least it supports the Set  P command

[batch-file] How to increment variable under DOS?

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