I recently saw this poll asking for the "Best Linux Clipboard Manager". What actually is a clipboard manager and in what situations would a clipboard manager be useful?
Are there some differences in the default clipboard behaviour of Ubuntu to other (Windows or Mac) systems?
Persistence is probably the best selling point for me. Most CBMs allow you to store the same items across sessions (even platforms), mobile (if your profile is) and especially in the case of X-based applications, selected items* are remembered after the source application closes (something that is not natively true).
Multiple clipboards is something I don't use too much but it' very handy if you find yourself juggling several bits and bobs at once. You can do all your copying at once and then get on with whatever you're doing. Less back-and-forth.
These are both negatives if you regularly copy sensitive data as it could be a security issue.
* Just an explanation: you do know you effectively get two clipboards out the box? There's the traditional Control+C, Control+V clipboard but there's also something called "primary selection". Select some text and then middle click where you want it pasted. I find this very useful for quick, precise, multiple pasting.
I tried a clipboard manager once called Parcellite and now I cannot live without it.
A clipboard manager is one of those things that you never need until you try it and then without realising it, you can't work properly without it.
Not only is it really useful when editing code and config files ( because you can store more than one thing on the clipboard at a time meaning you can cut a bit here, copy a bit here, paste the second bit, then paste the first bit and so on ) but it is also really useful as a quick temporary storage.
I use it to store URLs, phone numbers, configuration snippets etc, whilst I am working on something.
If it is something I want to keep for a while I will paste it into Tomboy but a lot of information you need is only required for perhaps fifteen minutes, and it is as easy as hitting Ctrl+C and it is there, using notes or files is over kill for this ort of information. Normally you would have to rely on your memory, or I believe you can use sliced up tress to store information too.
It is a brain extension that means I don't have to remember things.
There is a small but extremely annoying bug that more or less requires a clipboard manager to fix.
Take an application, like Firefox; copy some text or a picture then close Firefox, then try and dump it into a document. It won't work, because of a holdover from the UNIX days. The clipboard does not actually 'copy' it simply notes where to take the media from, and if you close the program it notes it down.
With a clipboard manager, you can get things like history and formatting stripping. Some clipboard managers even allow you to paste things across the network.
As for the differences between the cliboard behavior between windows and ubuntu, the only thing that comes to mind is that you have two clipboards: your normal copy+paste and highlight+middle-click.
If you have multiple files you want to rename still paste able after you copy something else.
I use xclip for copying commands i enter alot.
The main use is being able to copy more than once and being able to paste whichever you want.
For some repetive tasks, that call for the same 3 or 4 copies, it makes your life way easier to keep them in a manager. Even as opposed to keeping a gedit doc open with them in it as well.
I've found that it saves a good amount of time and is worth wild.
Maybe you don't want to use one. The nice bit about running one, however, is it doesn't get in your way if you never use it. This is what I do, and I rarely find it useful; but it won't (or shouldn't, at least) noticeably affect performance on 10 year old or newer desktop systems.
Perhaps I almost always don't need it because I do the majority of my text editing in [g]vim, which already has a similar feature through registers (:help registers if you're curious). Registers provide vim with a built-in clipboard manager, which works only inside vim; so if you want the same ease within another text editor (though I doubt it would be quite as easy), you could find one useful. Between vim and other programs, I just use the primary selection and regular clipboard, and that's been plenty.
Remember that you already have two "clipboards" on *nix systems: the primary selection plus the clipboard (there's actually more, but they're very rarely used). This is a feature of the X Window System. Whenever you select something (i.e. highlight), you can enter it in another program with a middle-click. Wikipedia's article isn't kidding that you'll predominately use the primary selection once you get used to it.
However, programs usually limit use of the primary selection to text. For example, open both nautilus and a text editor. Select a few files, then try to middle-click in the text editor: it won't work. (Nautilus doesn't acquire the primary selection so you'll get whatever was previously there, if anything. It could have been designed to do this differently, but it wasn't—I don't know if this was deliberate or not.) Copy those files to the clipboard (ctrl+c or edit > copy), then paste in your text editor to get the filenames.
In addition to the reasons you might deliberately want to use multiple clipboards (personally, I don't), they can work around a problem where some applications fail to retain their content on the clipboard when you quit them.
This is most visible (highly annoying) on Firefox on GNOME (see bug 311340 for teeth-grindingly slow progress).
Because you save a lots of time. Having the last 10 copied item ready to paste will you make a lot more productive.