Usage: watch [EXPRESSION]
watch
watch --delete [INDEX]
Evaluate an expression after every command and display it when its value
changes.
-d, --delete Delete the watch expression with the given index. If
no index is given; clear all watch expressions.
-l, --list Show all current watch expressions and their values.
Calling watch with no expressions or options will
also show the watch expressions.
The watch command will use Pry's command `state` to keep track of watched
expressions.
Conrad Irwin