Advanced Usage

Basic

• help
• cls - clear out the current screen
• session - check details of the current session
• reset - reset all empowered classes
• version - print the version of the Arthas attaching to the current target process
• quit/exit - exit the current Arthas client without affecting other clients
• shutdown - terminate the Arthas server and all clients

JVM-related

• dashboard - real-time dashboard for the current system
• thread - thread profile
• jvm - JVM profile
• sysprop - check or modify JVM system properties
• New! getstatic - check the static properties of some class

class/classloader - related

• sc - methods’ profile of the classes loaded by JVM
• sm - methods’ profile of the loaded classes
• dump - dump out the byte code of the loaded class to specified location
• redefine - load external *.class files and re-define the JVM
• jad - de-compile the specified loaded classes
• classloader - check the inheritance structure, urls, class loading info of class cloader; using classloader to getResource

monitor/watch/trace - related

Attention: commands here are taking advantage of byte code injection, which means we are using AOP to monitor and analyze the classes. So when using it for online troubleshooting, you’d better explicitly specifically specify the classes and also remember to remove the injected code by shutdown or reset (for specific classes).

• monitor
• watch
• trace - track the call stack trace and collect the time cost for each method call
• stack - print the call stack trace of the current method
• tt - record the arguments and returned value for the methods, history included

options

• options - check or set Arthas global options

pipe

pipe is supported in Arthas, e.g. sm org.apache.log4j.Logger | grep <init>

• grep
• plaintext - remove the color
• wc

async in background

async will be a great help, when the incident seldom occurs and you are [watch](watch.md)ing it.

• jobs - list all jobs
• kill - forcibly terminate the job
• fg - bring the paused job back to the front
• bg - put the paused job to the background
• tips - a) use > to redirect the output; b) use & to put the job to the background; c) disconnecting the session will not influence the job (the default life is 1 day)

Web Console

Using websocket to connect Arthas

• Web Console

Others

• log the output
• batch
• how to use ognl