In X10, "cut buffers" were introduced. These were limited buffers that stored arbitrary text and were used by most applications. However, they were inefficient and implementation of them varied, so selections were introduced. Cut buffers are long deprecated, and although some applications (such as xterm) may have legacy support for them, it is both not likely and not recommended that they be used.
The ICCCM (Inter-Client Communication Conventions Manual) standard defines three "selections": PRIMARY, SECONDARY, and CLIPBOARD. Despite the naming, all three are basically "clipboards". Rather than the old "cut buffers" system where arbitrary applications could modify data stored in the cut buffers, only one application may control or "own" a selection at one time. This prevents inconsistencies in the operation of the selections. However, in some cases, this can produce strange outcomes, such as a bidirectional shared clipboard with Windows (which uses a single-clipboard system) in a virtual machine.
Of the three selections, users should only be concerned with PRIMARY and CLIPBOARD. SECONDARY is only used inconsistently and was intended as an alternate to PRIMARY. Different applications may treat PRIMARY and CLIPBOARD differently; however, there is a degree of consensus that CLIPBOARD should be used for Windows-style clipboard operations, while PRIMARY should exist as a "quick" option, where text can be selected using the mouse or keyboard, then pasted using the middle mouse button (or some emulation of it). This can cause confusion and, in some cases, inconsistent or undesirable results from rogue applications.
List of clipboard managers
- Anamnesis — Clipboard manager that stores all the clipboard history and offers an interface to do a full-text search. It has both a commandline and GUI mode available.
- ClipIt — Fork of Parcellite with additional features and bugfixes.
- Clipman — A clipboard manager for Xfce. It keeps the clipboard contents around while it is usually lost when you close an application. It is able to handle text and images, and has a feature to execute actions on specific text selections by matching them against regular expressions.
- CopyQ — Clever clipboard manager with searchable and editable history, custom actions on items and command line support.
- Glipper — Clipboard manager for the GNOME desktop with many features and plugin support.
- GPaste — Clipboard management system that aims at being a new generation Parcellite, with a modular structure split in a couple of libraries and a daemon for adaptability. Offers a GNOME Shell extension and a CLI interface.
- Klipper — Full featured clipboard manager for the KDE desktop.
- loliclip — Clipboard synchronizer developed for window manager users. Development ceased in favour of xcmenu.
- Parcellite — Lightweight yet feature-rich clipboard manager.
- Pasteall — Clipboard monitor simple and functional.
- xcmenu — Clipboard synchronizer developed for window manager users.