批处理脚本以删除特定计数值后目录中的文件

Question

I am currently looking to implement a small script to browse through a directory and delete all files/folders after a certain count value in this case ill use 3

This is an example of what i'm trying to achieve

c:/test Contains

1. file1.bak
2. file2.bak
3. file3.bak
4. file4.bak (delete)
5. file5.bak (delete)
6. file6.bak (delete)

I am not very familiar with batch scripting but believe the process will require a for iteration that adds 1 to a count variable for every file (of any type) in the directory and when the count reaches 3 it will begin to delete files after that point. Could someone please assist I can write the base process in Java but am slightly unfamiliar with batch scripting. Could someone please assist?

Thanks

Answer 1

There is no need for a counter

@echo off
    setlocal enableextensions disabledelayedexpansion

    rem How many elements to keep
    set "keep=3"

    rem Retrieve folder from batch arguments
    set "folder=%~1"

    rem If no folder indicated, use current active directory
    if not defined folder for %%a in (.) do set "folder=%%~fa"

    rem Ensure we are working in the correct folder
    pushd "%folder%" && (
        rem For each element in the folder, skipping the first n 
        for /f "skip=%keep% delims=" %%a in (' dir /b /on ') do (
            rem If it is a folder, use rmdir, else use del
            if exist "%%a\" ( echo rmdir /s /q "%%a" ) else ( echo del "%%a" )
        )
        rem Work done. Return to previous active directory
        popd
    ) || ( 
        rem Folder change failed
        echo Target folder does no exist 
    )

File/folder removal operations are only echoed to console. If the output is correct, remove the echo commands that precede rmdir and del

Answer 2

Not tested.Change the directory , number and etc variables at the beginning of the file.And its ok delete the echo at the last line

@echo off
set "start_deleting_from=4"
set "directory=c:\bak_files"
set "extension=.bak"
set counter=0

pushd "%directory%"
setlocal enableDelayedExpansion
for %%# in (%extension%) do (
  set /a counter=counter+1
  if !counter! GEQ !start_deleting_from! (
   rem delete "echo" if to activate deletion
   echo del /q /f file!counter!!extension!
 )
)

Answer 3

So if the requirement is "when alphabetically sorted, keep the top three of the *.bak files in the folder and delete the rest" , the batch file would be:

@echo off
setlocal EnableDelayedExpansion

pushd C:\test
set top=3
set filespec=*.bak
set counter=0

for /f "delims=" %%f in ('dir /b %filespec%') do (
    set /a counter+=1
    if !counter! GTR %top% del /q "%%f"
)

You can use the various options of the dir command to achieve different orders or select different files.

---

You could use also use command line arguments to configure the script. Assuming you call the script like this:

delete_after.bat 3 *.bak

then 3 and *.bak are available inside the batch file as %1 and %2 , respectively. You can use that to get rid of the hard-coded values.