Here is a fully commented batch code for creating or updating desktop.ini for a folder icon and optionally also for folder type for either a specified folder or all folders in root of current drive (or current directory with deleting/commenting a single line).
Creating a desktop.ini is quite simple as it can be seen by looking on code. Updating an existing INI file to replace lines or add them if necessary in correct section is much more difficult on using only internal commands of Windows command processor cmd.exe which is not designed for such tasks.
@echo off
rem CreateDesktopIni.bat [FolderName | FolderType] [FolderType]
rem This batch file can be started without any parameter to create or
rem update desktop.ini for all subfolders in root of current drive or
rem current working directory with removing or commenting one line in
rem code below, see comment below label AllFolders.
rem But the batch file can be also started with a folder name
rem to create or update file desktop.ini of this folder only.
rem Optionally it is possible to specify as only parameter a folder type
rem or append as second parameter after folder name the folder type.
rem The folder type can be one of the following strings (not verified):
rem CommonDocuments, Contacts, Documents, Music, MusicAlbum, MusicArtist,
rem MusicIcons, MyDocuments, MyMusic, MyPictures, MyVideos, PhotoAlbum,
rem Pictures, UseLegacyHTT, VideoAlbum, Videos
setlocal EnableExtensions DisableDelayedExpansion
set "FolderType=%~2"
rem Define the subfolder containing the icon for the folder.
set "IconFolder=Icon"
rem Is the batch file called with at least one parameter?
if "%~1" == "" goto AllFolders
rem Yes! It could be a folder name or the folder type.
if not exist "%~1" set "FolderType=%~1" & goto AllFolders
rem First parameter specifies a folder (most likely as not verified).
set "Folder=%~1"
rem Remove trailing backslash if there is one.
rem The batch file should not be called with just \ as folder path.
if "%Folder:~-1%" == "\" set "Folder=%Folder:~0,-1%"
rem Call subroutine to create or update the desktop file for this folder.
call :DesktopINI "%Folder%"
goto EndBatch
:AllFolders
rem Change working directory to root of current drive. Remove or comment
rem the next line to process instead all subfolders in current directory.
cd \
rem Call subroutine to create/update the desktop file for each subfolder.
for /F "eol=| delims=" %%I in ('dir /AD /B 2^>nul') do call :DesktopINI "%%I"
goto EndBatch
rem Subroutine to create or update the desktop file for a folder.
rem This subroutine first searches for the icon file and does nothing
rem if no icon file could be found in the defined subfolder because
rem the subfolder does not exist at all or there is no *.ico file.
rem After determining the icon file (first found *.ico file) with full path
rem including drive letter (remove character d for relative path without
rem drive letter in line with %%~dpnxI), this subroutine checks next for
rem existence of file desktop.ini (case-insensitive) in current folder.
rem desktop.ini with the two or three lines is simply created if this file
rem does not already exist and the user of the batch file has permissions
rem to create this file in the current folder.
rem For an already existing desktop.ini the necessary process to update it
rem is much more complex. All lines outside the section [.ShellClassInfo]
rem must be kept and are therefore just copied to a temporary file, except
rem empty lines ignored by command FOR. Also all lines within the section
rem [.ShellClassInfo] not starting with the string IconFile= or optionally
rem FolderType= (both case-insensitive) must be also simply kept by copying
rem them to the temporary file.
rem An existing line starting with IconFile= in section [.ShellClassInfo]
rem is not copied to temporary file, but instead this line is written to
rem the temporary file with determined icon file name with path.
rem An existing line starting with FolderType= in section [.ShellClassInfo]
rem is also not copied to temporary file, but instead this line is written
rem to the temporary file with folder type as specified on starting batch.
rem If section [.ShellClassInfo] was found and beginning of a new section is
rem detected because of a line starting with an opening square bracket and
rem the line with IconFile= and/or the line with FolderType= was not found
rem in this section during processing the existing desktop.ini, the lines
rem are written next to temporary file to insert them before continuing
rem with the next section.
rem Finally it could happen that section [.ShellClassInfo] is missing in
rem existing desktop.ini and must be therefore added to the file. And it
rem could be that this section exists at end of desktop.ini, but either
rem the line with IconFile= or with FolderType= or both are missing and
rem those lines must be therefore appended to the file.
rem The temporary file is next copied over the existing desktop.ini and
rem then deleted as not further needed. Finally the system and hidden
rem attributes are set on file desktop.ini and the system attribute is
rem set on the current folder as otherwise desktop.ini would be ignored.
:DesktopINI
set "Folder=%~1"
for %%I in ("%Folder%\%IconFolder%\*.ico") do (
set "IconFile=%%~dpnxI"
goto IconFound
)
goto :EOF
:IconFound
set "DesktopFile=%Folder%\desktop.ini"
if not exist "%DesktopFile%" (
echo [.ShellClassInfo]>"%DesktopFile%"
if not exist "%DesktopFile%" goto :EOF
echo Iconfile=%IconFile%>>"%DesktopFile%"
if defined FolderType echo FolderType=%FolderType%>>"%DesktopFile%"
%SystemRoot%\System32\attrib.exe +h +s "%DesktopFile%"
%SystemRoot%\System32\attrib.exe +s "%Folder%"
goto :EOF
)
set "IconLine="
set "ShellClassInfo="
set "UpdateComplete="
set "TempFile=%TEMP%\Desktop.tmp"
if exist "%TempFile%" del /F "%TempFile%"
if not defined FolderType (set "TypeLine=1") else set "TypeLine="
%SystemRoot%\System32\attrib.exe -h -s "%DesktopFile%"
(for /F "usebackq delims=" %%L in ("%DesktopFile%") do (
set "LineOutput="
if defined ShellClassInfo (
for /F "delims==" %%V in ("%%L") do (
if /I "%%V" == "IconFile" (
echo Iconfile=%IconFile%
set "IconLine=1"
set "LineOutput=1"
) else if /I "%%V" == "FolderType" (
if defined FolderType (
echo FolderType=%FolderType%
set "TypeLine=1"
set "LineOutput=1"
)
) else (
set "NewSection=1"
for /F "eol=[" %%G in ("%%V") do set "NewSection="
if defined NewSection (
if not defined IconLine echo Iconfile=%IconFile%
if not defined TypeLine echo FolderType=%FolderType%
set "ShellClassInfo="
set "UpdateComplete=1"
)
)
)
) else if /I "%%L" == "[.ShellClassInfo]" (
echo [.ShellClassInfo]
set "ShellClassInfo=1"
set "LineOutput=1"
)
if not defined LineOutput echo(%%L
)) >"%TempFile%"
if not defined UpdateComplete if not defined ShellClassInfo (
echo [.ShellClassInfo]>>"%TempFile%"
set "ShellClassInfo=1"
)
if defined ShellClassInfo (
if not defined IconLine echo Iconfile=%IconFile%
if not defined TypeLine echo FolderType=%FolderType%
) >>"%TempFile%"
move /Y "%TempFile%" "%DesktopFile%" >nul
if exist "%TempFile%" del "%TempFile%"
%SystemRoot%\System32\attrib.exe +h +s "%DesktopFile%"
%SystemRoot%\System32\attrib.exe +s "%Folder%"
goto :EOF
:EndBatch
endlocal
It is advisable to remove all comments which are the lines starting with command rem for faster processing of the batch file.
The command line cd \ must be removed or commented out if the batch file should process all subfolders of the current folder on starting the batch file instead of the subfolders of the current drive.
The DIR option /S can be appended to dir /AD /B to process the entire directory tree of current folder or current drive on start of this batch file.
The environment variable IconFolder can be defined with just . instead of Icon to search for first *.ico file in the folder itself instead of a subfolder Icon.
To understand the commands used and how they work, open a command prompt window, execute there the following commands, and read the displayed help pages for each command, entirely and carefully.
attrib /?call /?cd /?del /?dir /?echo /?endlocal /?for /?goto /?if /?move /?rem /?set /?setlocal /?
Read the Microsoft article about Using command redirection operators for an explanation of > and >> and 2>nul. The redirection operator > must be escaped with caret character ^ on FOR command line with 2^>nul to be interpreted as literal character when Windows command interpreter processes this command line before executing command FOR which executes the embedded dir command line with using a separate command process started in background.
