Retrieve and set the X selection.

The X server maintains three selections, called PRIMARY, SECONDARY and CLIPBOARD. The PRIMARY selection is conventionally used to implement copying and pasting via the middle mouse button. The SECONDARY and CLIPBOARD selections are less frequently used by application programs. This program operates on the PRIMARY selection unless otherwise specified.

By default, this program outputs the selection without modification if both standard input and standard output are terminals (ttys). Otherwise, the current selection is output if standard output is not a terminal (tty), and the selection is set from standard input if standard input is not a terminal (tty). If any input or output options are given then the program behaves only in the requested mode.

If both input and output is required then the previous selection is output before being replaced by the contents of standard input.

Input options

-a, --append

append standard input to the selection. Implies -i.

-f, --follow

append to selection as standard input grows. Implies -i.

-i, --input

read standard input into the selection.

Output options

-o, --output

write the selection to standard output.

Action options

-c, --clear

clear the selection. Overrides all input options.

-d, --delete

Request that the current selection be deleted. This not only clears the selection, but also requests to the program in which the selection resides that the selected contents be deleted. Overrides all input options.

Selection options

-p, --primary

operate on the PRIMARY selection (default).

-s, --secondary

operate on the SECONDARY selection.

-b, --clipboard

operate on the CLIPBOARD selection.

-k, --keep

Do not modify the selections, but make the PRIMARY and SECONDARY selections persist even after the programs they were selected in exit. (Conventionally, the CLIPBOARD selection is persisted by a separate special purpose program such as xclipboard(1)). Ignores all input and output options.

-x, --exchange

exchange the PRIMARY and SECONDARY selections. Ignores all input and output options.

X options

-d displayname, --display displayname

specify the server to use; see X(1).

-t ms, --selectionTimeout ms

Specify the timeout in milliseconds within which the selection must be retrieved. A value of 0 (zero) specifies no timeout (default).

Miscellaneous options

-l filename, --logfile filename

Specify the file to log errors to when detached. (Default $HOME/.xsel.log)

-n, --nodetach

Do not detach from the controlling terminal. Without this option, xsel will fork to become a background process in input, exchange and keep modes.

-h, --help

display usage information and exit

-v, --verbose

Print informative messages. Additional instances of -v raise the debugging level, ie. print more information.

-v, --version

output version information and exit

There is no X selection buffer. The selection mechanism in X11 is an interclient communication mediated by the X server each time any program wishes to know the selection contents, eg. to perform a middle mouse button paste. In order to implement modification of the selection(s) (in input, keep and exchange modes) this program detaches from the terminal, spawning a child process to supply the new selection(s) on demand. This child exits immediately when any other program takes over the selection(s), eg. when the user next selects some text in a terminal window or by running xsel -c.