How to delete all files that don't have a certain string in their name

Solution 1:

How can I delete zip files in a folder/subfolders that don't have "MS" in their name?

Use the following batch file:

@echo off
setlocal disableDelayedExpansion
for /f "usebackq tokens=*" %%i in (`dir /a:-d /b /s *.zip ^| findstr /v "[\\][^\\]*MS[^\\]*$"` ) do (
  echo del /s /q %%i
)
endlocal

Notes:

• Remove the echo when you are happy with what the batch file will do.
• Answer updated as per comment by dbenham to allow for directories containing the string "MS"
• Answer updated to handle filenames containing spaces.

Further Reading

• An A-Z Index of the Windows CMD command line - An excellent reference for all things Windows cmd line related.
• del - Delete one or more files.
• dir - Display a list of files and subfolders.
• findstr - Search for strings in files.
• for /f - Loop command against the results of another command.