CopyCat allows you to copy items from one chest to another and copy text from one sign to the other using commands. It is very lightweight, and requires no configuration. It's as simple as copy and paste on your computer!
All you have to do is use one of the copy commands below, and then left click on a certain item you want copied. Then, when you see, "Copy successful!", use a paste command and then left click on the item you want it pasted on.
This plugin can be very useful if you want multiple chests of the same items, or signs with the same exact text.