Update cheatsheets

tldr/arthas-watch

@@ -0,0 +1,22 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# arthas-watch
+
+> Method invoke data observation.
+> See also: `arthas`, `arthas-trace`.
+> More information: <https://arthas.aliyun.com/en/doc/watch.html>.
+
+- Observe the first parameter and return value of method, and expand the nested attributes of the object to 4 levels:
+
+`watch {{class-pattern}} {{method-pattern}} {{'{ params[0],returnObj }'}} -x 4`
+
+- When the value of the first parameter of the method is 5, the second parameter and return value are output, and the object is expanded 4 layers:
+
+`watch {{class-pattern}} {{method-pattern}} {{'{ params[1],returnObj }'}} {{'"5".equals(params[0])'}} -x 4`
+
+- When the method returns or an exception occurs, observe the count property of the second parameter:
+
+`watch {{class-pattern}} {{method-pattern}} {{'{ params[1].count }'}} -e -s`