You are working on an existing rails project with many rubocop warnings and you would like to fix certain types or warnings by getting only the specified files.
So for example when you use rubocop you first get the following for all the files in the project:
rubocop 799 files inspected, 17214 offenses detected
You can get a grouping of the errors by using the following:
rubocop --format offenses 7176 Style/StringLiterals 3596 Metrics/LineLength 1031 Style/VariableName 790 Style/IndentationConsistency 548 Style/SpaceAroundOperators 423 Style/Documentation 415 Style/HashSyntax 386 Style/TrailingWhiteSpace 198 Style/SpaceAfterComma ...
If you would like to know only the files for a certain type of warning to be able to fix them you could try the following:
rubocop --only Style/TrailingWhitespace ..... list of files 799 files inspected, 386 offenses detected