Check out example codes for "kotlin checkstyle". It will help you in understanding the concepts better.

Code Example 1

./gradlew checkstyle

Code Example 2

# check the style of all Kotlin files inside the current dir (recursively)
# (hidden folders will be skipped)
$ ktlint
  src/main/kotlin/Main.kt:10:10: Unused import
# check only certain locations (prepend ! to negate the pattern) 
$ ktlint "src/**/*.kt" "!src/**/*Test.kt"

# auto-correct style violations
# (if some errors cannot be fixed automatically they will be printed to stderr) 
$ ktlint -F "src/**/*.kt"

# print style violations grouped by file
$ ktlint --reporter=plain?group_by_file
# print style violations as usual + create report in checkstyle format 
$ ktlint --reporter=plain --reporter=checkstyle,output=ktlint-report-in-checkstyle-format.xml

# install git hook to automatically check files for style violations on commit
$ ktlint --install-git-pre-commit-hook

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