CLI is way to call pdf regression service from command line level. It can be easily incorporated as part of your CI workflow.
For parameters description check analogous endpoints in API section.
java -jar pdfregression.jar --baseFile=a.pdf --testFile=b.pdf --apiKey=xxx
java -jar pdfregression.jar --baseFileUrl=https://my-test-site.com/test/t5a.pdf --testFileUrl=https://my-test-site.com/test/t5b.pdf --apiKey=xxx
java -jar pdfregression.jar --baseFile=t5a.pdf --testFile=t5b.pdf --apiKey=xxx --ignoreRegionsJson=[{\"x\":0,\"y\":0,\"width\":1000,\"height\":1000,\"page\":0}]
java -jar pdfregression.jar --baseFile=t5a.pdf --testFile=t5b.pdf --timeout=30 --apiKey=xxx