issues with enabledelayedexpansion for file renaming batch script

Question

i am writing a batch script monotonic file renamer. basically, it makes the titles of all the files 1 2 3 4 .... and so on. i have since expanded it to be able to handle files of different types (txt, doc, flv, etc) but not everything is working out.

my main concern is i have broken the delayed expansion calls i was making before. now using !var1! is never expanded, or never recognized as a variable.

here is a verbosely commented version of my script

::a monotonic file renamer
@echo off
SETLOCAL ENABLEDELAYEDEXPANSION

SET tempfile=temp.txt
SET exttemp=exttemp.txt
if [%1] == [] goto usage

::make sure your dont overwrite something useful
if EXIST %tempfile% (
ECHO Temp file already exists, are you sure you want to delete?
del /P %tempfile%
)
if EXIST %exttemp% (
ECHO EXT Temp file already exists, are you sure you want to delete?
del /P %exttemp%
)

::initialize 
SET /a counter=0
SET type=
SET /a ender=%1

::write filenames to tempfile
DIR /B /ON > %tempfile%

::read lines one by one
for /f "usebackq delims=" %%a in (%tempfile%) do (
REM make sure we do not rename any of the working files
if NOT "%%a"=="renamer.bat" (
if NOT "%%a"=="temp.txt" (
if NOT "%%a"=="exttostr.bat" (
SET /a counter+=1
REM get file extension
exttostr %%a > %exttemp%
SET /P type= < %exttemp%
REM housekeeping
del /F %exttemp%
REM rename
ren %%a !counter!.!type!
ECHO Renamed "%%a" to "!counter!.!type!"
)))
REM exit when we have run enough
if "!counter!"=="!ender!" goto exit
)

goto exit

:usage
echo Usage: renamer NUMFILES

:exit
::final housekeeping
DEL temp.txt

the idea is i drop my two files, renamer.bat(this file) and exttostr.bat(helper to get the file extension) into the folder and run it, it will rename files sorted alphabetically from 1 to how ever many files i specify.

when i run the code, it never uses the variables marked for delayed expansion appropriately, always leaving them as "!varname!", so it renames the first file "!counter!.!type!" and throws errors for the rest because there is already a file in the directory with that name.

this brings me to a secondary issue. sorting the dir list alphabetically results in a poor handling of numbered files. for example the list: "1 7 15 75 120" is sorted: "1 120 15 7 75" i have not been able to find a way around this yet, only that it is indeed the intended result of the dir sort. the only workaround i have is padding numbers with enough zeroes in the front.

thanks in advance for any insight!

---

everything is sorted but the second problem. i think i have not spoken well. i have this issue when i take IN the directory file names, not when writing out. so they already need to be padded. i has hoping there was some other way to read the directory and have it be sorted appropriately.

the most promising thing i have found is here: http://www.dostips.com/DtCodeBatchFiles.php#Batch.SortTextWithNumbers

    @ECHO OFF
if "%~1"=="/?" (
    echo.Sorts text by handling first number in line as number not text
    echo.
    echo.%~n0 [n]
    echo.
    echo.  n     Specifies the character number, n, to
    echo.        begin each comparison.  3 indicates that
    echo.        each comparison should begin at the 3rd
    echo.        character in each line.  Lines with fewer
    echo.        than n characters collate before other lines.
    echo.        By default comparisons start at the first
    echo.        character in each line.
    echo.
    echo.Description:
    echo.        'abc10def3' is bigger than 'abc9def4' because
    echo.        first number in first string is 10
    echo.        first number in second string is 9
    echo.        whereas normal text compare returns 
    echo.        'abc10def3' smaller than 'abc9def4'
    echo.
    echo.Example:
    echo.        To sort a directory pipe the output of the dir
    echo.        command into %~n0 like this:
    echo.           dir /b^|%~n0
    echo.
    echo.Source: http://www.dostips.com
    goto:EOF
)

if "%~1" NEQ "~" (
    for /f "tokens=1,* delims=," %%a in ('"%~f0 ~ %*|sort"') do echo.%%b
    goto:EOF
)
SETLOCAL ENABLEDELAYEDEXPANSION
set /a n=%~2+0
for /f "tokens=1,* delims=]" %%A in ('"find /n /v """') do (
    set f=,%%B
    (
        set f0=!f:~0,%n%!
        set f0=!f0:~1!
        rem call call set f=,%%%%f:*%%f0%%=%%%%    
        set f=,!f:~%n%!
    )
    for /f "delims=1234567890" %%b in ("!f!") do (
        set f1=%%b
        set f1=!f1:~1!
        call set f=0%%f:*%%b=%%
    )
    for /f "delims=abcdefghijklmnopqrstuwwxyzABCDEFGHIJKLMNOPQRSTUWWXYZ~`@#$*_-+=:;',.?/\ " %%b in ("!f!") do (
        set f2=00000000000000000000%%b
        set f2=!f2:~-20!
        call set f=%%f:*%%b=%%
    )
    echo.!f1!!f2!!f!,%%B
    rem echo.-!f0!*!f1!*!f2!*!f!*%%a>&2
)

this code can sort the filenames with one number in them (i.e. video100.mov is fine, video100video10.mov would break it)

the issue i have is i think adding a call to this helper fn will break it again, so i will be trying to include this in my modified renamer.bat now. any help is appreciated.

Answer 1

I didn't experience any issues with delayed expansion, everything worked fine for me (except, of course, for the fact that I didn't have the exttostr.bat helper script.)

Anyway, there are several things that could be improved about your script:

1. You don't need to store the result of DIR into a file to read it afterwards. You can read the output directly in the FOR loop.

2. You don't need the helper batch script. The extension can be extracted from %%a by using the ~x modifier with the loop variable: %%~xa. You can read more about modifiers by issuing HELP FOR from the command prompt.

3. The renamer batch file's own name can be referenced in the script as %0. You can apply the ~n modifier where you only need to use the name without the extension. The combined modifier of ~nx will give you the name with the extension.

So, here's how your script might look like with the above issues addressed:

::a monotonic file renamer
@echo off
SETLOCAL ENABLEDELAYEDEXPANSION

IF [%1] == [] GOTO usage

::initialize 
SET /A counter=0
SET type=
SET /A ender=%1

::read lines one by one
FOR /F "usebackq delims=" %%a IN (`DIR /B /ON`) DO (
  REM make sure we do not rename any of the working files
  IF NOT "%%~a"=="%~nx0" (
    SET /A counter+=1
    RENAME "%%~a" "!counter!%%~xa"
    ECHO Renamed "%%~a" to "!counter!%%~xa"
  )
  REM exit when we have run enough
  IF "!counter!"=="!ender!" GOTO :EOF
)

GOTO :EOF

:usage
ECHO Usage: %~n0 NUMFILES

As for your secondary issue, it can be easily resolved like this:

1. Use something like 100000 as counter's initial value. (Use however many 0s you like, but possibly no more than nine.) Add the same value to ender as well.

2. When renaming files, instead of !counter! use the expression that removes the first character (the 1): !counter:~1! (in fact, this is not about removal, but about extracting a substring starting from the offset of 1, learn more about it with the HELP SET command).

Here's the modified version of the above script:

::a monotonic file renamer
@echo off
SETLOCAL ENABLEDELAYEDEXPANSION

IF [%1] == [] GOTO usage

::initialize 
SET /A counter=1000
SET type=
SET /A ender=%1
SET /A ender+=counter

::read lines one by one
FOR /F "usebackq delims=" %%a IN (`DIR /B /ON`) DO (
  REM make sure we do not rename any of the working files
  IF NOT "%%~a"=="%~nx0" (
    SET /A counter+=1
    RENAME "%%~a" "!counter:~1!%%~xa"
    ECHO Renamed "%%~a" to "!counter:~1!%%~xa"
  )
  REM exit when we have run enough
  IF "!counter!"=="!ender!" GOTO :EOF
)

GOTO :EOF

:usage
ECHO Usage: renamer NUMFILES

You can also see that I made some other enhancements, like making sure the file name is enclosed in double quotes, and using GOTO :EOF instead of GOTO exit (:EOF is a special pre-defined label that points at the end of the batch script so you don't need to define your own).

Answer 2

Probably the batch for extracting the extension reset the local environment.

But, you don't need it. You may extract the extension with the ~x option. Something similar to this ....

:monotonicrename
set /a counter = 0
for %%a in (%1\*.*) do (
  if exist %%~fa (
    set /a counter += 1
    echo ren %%~fa !counter!%%~xa 
  )
)
goto :eof

to include leading zeroes in the counter, so that the directory sorts correctly, replace the previous rename command with three lines

set zcounter=0000!counter!
set zcounter=!zcounter:~-4!
echo ren %%~fa !counter!%%~xa 

So putting all pieces together, add the monotonicrename function you just created in the batch file that can be as simpler as...

@echo off
setlocal enabledelayedexpansion
call :monotonicrename %1
goto :eof
:monotonicrename
set /a counter = 0
for %%a in (%1\*.*) do (
  if exist %%~fa (
    set /a counter += 1
    set zcounter=0000!counter!
    set zcounter=!zcounter:~-4!
    echo ren %%~fa !zcounter!%%~xa 
  )
)
goto :eof