xcopy – read and write text to/from an X selection from the command line
xcopy [ -r ] [ -u | -c ] [ -C ]
xcopy is a command-line utility for manipulating the X selection.
It has two basic modes. In read mode (
xcopy -r), it connects to your X server, retrieves the contents of the selection as plain text, and writes it on standard output. You would then typically redirect its output into a file, or pipe it into some other program.
In write mode (just
-r is not specified), it will read data from standard input, then connect to your X server and place that data in the selection as plain text. So you can pipe data into
xcopy, move to another application, and press Paste.
The X selection model requires the selection-owning client to remain connected to the server and hand out its data on request. Therefore,
xcopy in write mode forks off a background process which does this. The background process terminates once it is no longer the selection owner (i.e. as soon as you select data in another application), or if your X session finishes. Normally you can ignore its presence, although it might become important to be aware of it if (for example) the
xcopy background process were to be the last X client still connected through an SSH tunnel.
xcopy currently only handles text data. However, it is capable of handling it in the form of plain text, UTF-8, or compound (multiple-character-set) text. Use the
-C options to control this aspect of its behaviour.
xcopy can also support the source end of the Xdnd protocol for drag and drop (since it's closely related to selections). Use the
--drop option to manually set up a drag-and-drop of some data, and then click in a window where you want to drop it.
By default (if
-r is not supplied),
xcopy operates in write mode.
xcopyinto read mode.
By default (if neither
-u is supplied),
xcopy reads and writes the selection using the type
STRING, which means that the input or output data is expected to be encoded in ISO-8859-1.
xcopyto request the selection using the type
UTF8_STRING, which typically means that the returned data will be encoded as UTF-8. In write mode, causes
xcopyto give out the selection as type
UTF8_STRING, meaning that the data piped in to it is expected to be encoded as UTF-8.
-u, but uses the type
COMPOUND_TEXTis a complex multi-character-set encoding similar to ISO 2022, and is unlikely to be a very useful form in which to pass data to or from non-X programs. However, it might occasionally be useful to retrieve a compound text selection using
xcopy -r -c, and later on return it to the X selection using
xcopy -cso it can be pasted back into a different application.
In write mode, if
xcopy is operating in
STRING mode and a pasting application requests the selection as
xcopy will convert the data automatically. This is normally what you want.
-Cto disable conversion to compound text.
-c, these two options change the type of the selection data. This time, they set it to the string ‘
text/html’, which is a selection format used by at least Firefox when you select or copy text on a web page.
-H retrieves the ‘
text/html’ selection data in its raw format, which is encoded in UTF-16.
-h automatically converts between that and UTF-8, which is generally more useful in a mostly UTF-8 oriented world.
xcopyto read or write the clipboard instead of the selection. (Modern GNOME and KDE-style programs can often interact with both. The selection is the traditional X-style storage location which you typically copy things into just by selecting them with the mouse, and paste with the middle mouse button. The clipboard is a more Windows-like location which you access using explicit Cut, Copy and Paste commands in your application.)
xcopy, in read mode only, to return the list of possible target types currently stored in the selection. This is probably only useful for debugging X applications or X selection issues.
xcopy, in read mode only, to return the time stamp for the current selection. This is probably only useful for debugging X applications or X selection issues.
xcopyto request (in read mode) or announce (in write mode) the selection contents with a user-specified target data type. For read mode, the target type can be anything listed by ‘
xcopy -r -t’. For write mode, you can choose anything you think the pasting application will support.
xcopy, in read mode only, to produce a verbose commentary on the progress of reading the X selection. Can be useful for debugging interactions with other programs.
xcopynot to fork, when in write mode. Instead the original
xcopyprocess will continue to run until the selection is taken away from it. Probably only useful when debugging
xcopyitself, although it's just possible that it might turn out to be useful for some other special purpose (e.g. having the process waiting for it know when the selection owner has changed).
xcopy. (Probably most useful for diagnostic purposes.)
xcopy, in write mode, from using the
INCRmechanism for transferring large amounts of selection data a piece at a time and waiting for the recipient to acknowledge each chunk before sending the next. (Just in case a client doesn't support it.)
xcopy, in write mode, from storing its data in the persistent ‘cut buffers’ on the root window as well as using the peer-to-peer selection mechanism.
xcopyinto drag-and-drop mode.
xcopywill take control of the mouse pointer, similar to the way
xprop(1) does, and allow you to click on an application to receive the dragged-and-dropped data. The data itself is piped into
xcopy's standard input, just as if it were being placed in a selection (which it is, in fact – that's how the Xdnd protocol works). Click the left button over an eligible receiving window to drop data there; click the middle or right button to cancel the drop and terminate
Automatic conversion between compound text and UTF-8 is not currently supported. There are Xlib functions to do it, although they don't appear to work very well (missing out many characters which they could have converted).
xcopy is free software, distributed under the MIT licence. Type
xcopy --licence to see the full licence text.