At the bottom of this page on the website:
" It is possible to run Checkstyle directly from the
JAR file using the -jar option. An example would be:
java -jar checkstyle-all-4.1.jar \ -c
The backslash is incorrect.
I suspect it needs to be moved to the end of the line
to serve as a contintinuation character.
The command might want to be shown in courier font like
the other examples on the page.