Question

I am writing a batch file to run on Windows server 2008 R2, it has a for loop in it and no matter how many tutorials I read online and try, it won’t run the for loop.

echo "Starting blur detection..."
if not exist %root%\output mkdir output
set tempnum = dir root | find /i "file"
set num = tempnum-5
for /l %idx in (0, 1, num) do (
   %root%\blurDetection.exe %root%\%img%__%idx%.tif %root%\output
   echo "blurDetection" %idx " of " %num )

Windows powershell says “idx was unexpected at this time.”
Any suggestions?

EDIT: Actually I think this line is causing the problem, I don’t think it is getting and integer value in return.

set tempnum = dir root | find /i "file"

Answer 1

(added after initial post) Oh and I missed the biggest issue. Which is indeed this line:

set tempnum = dir root | find /i "file"

You mean to capture the output of dir, right? This can, AFAIK only be done inside for, unless you can live with outputting into a file and using that as input later.

Syntax is in such a case:

FOR /F ["options"] %variable IN ('command') DO command [command-parameters]

Note: those are not backticks.

Best explanations for NT scripting for: http://www.robvanderwoude.com/ntfor.php

One more note: since you appear to rely on the file name as some number, I suspect that dir /b would be the better choice. Plain dir will also output date and file size etc …

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IIRC names of for variables cannot have more than one letter. Also, inside script files (as apposed to the command line) those variables look like this:

%%i

Besides, the

set num=tempnum-5

should probably be

set /a num=%tempnum%-5

Another question about find is whether you meant to use findstr. Too little context, but findstr seems more natural.

From for /?:

FOR %variable IN (set) DO command [command-parameters]

  %variable  Specifies a single letter replaceable parameter.
  (set)      Specifies a set of one or more files.  Wildcards may be used.
  command    Specifies the command to carry out for each file.
  command-parameters
             Specifies parameters or switches for the specified command.

To use the FOR command in a batch program, specify %%variable instead
of %variable.  Variable names are case sensitive, so %i is different
from %I.

Note in particular these two statements:

• %variable Specifies a single letter replaceable parameter.
• To use the FOR command in a batch program, specify %%variable instead of %variable.

Another peculiar feature of for loops is that you can split your input and tokens will get assigned to variables in alphabetical order. So inside a for %a ... tokens would get assigned to %a, %b and so forth …set tempnum = dir root | find /i “file”