This Jekyll plugin defines the following Jekyll filters that return portions of a string: begins_with — returns true if a string starts with a given substring. does_not_begin_with — returns false if a string starts with a given substring. ends_with — returns true if a string end with a given substring. does_not_end_with — returns false if a string end with a given substring. append_suffix_if_does_not_start_with — appends a suffix to the string if the string does not start with a substring.