When you run mvn checkstyle:check, it will either succeed or fail if you
have any checkstyle violations. And when it fails, it unfortunately doesn't
print the violations and their locations by default. Here's a convenient
snippet to do this:
#!/bin/bash
mvn checkstyle:checkstyle \
--quiet \
-Dcheckstyle.enable.files.summary=false \
-Dcheckstyle.enable.rules.summary=false \
-Dcheckstyle.enable.severity.summary=false \
-Dcheckstyle.enable.rss=false \
-Dcheckstyle.output.file=/dev/stdout \
-Dcheckstyle.output.format=plain