Delete recursively hidden files in Windows
Example
Delete recursively all files starting with ._
del /s /q /h:A "._*"
Source: https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/del
To search every file in the current directory and all subdirectories that contained a word, regardless of the letter case
Example
Find the word "Windows"
findstr /s /i Windows *.*
Source: https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/findstr