Find a specified string in files. More information: https://learn.microsoft.com/windows-server/administration/windows-commands/find.
find "{{string}}" {{path\to\file_or_directory}}
find "{{string}}" {{path\to\file_or_directory}} /v
find "{{string}}" {{path\to\file_or_directory}} /c
find "{{string}}" {{path\to\file_or_directory}} /n