xcutsel - interchange between cut buffer and selection
xcutsel [ -toolkitoption ...] [-selection selection]
  [-cutbuffer number]
The xcutsel program is used to copy the current selection into a cut
  buffer and to make a selection that contains the current contents of the cut
  buffer. It acts as a bridge between applications that don't support selections
  and those that do.
By default, xcutsel will use the selection named PRIMARY
    and the cut buffer CUT_BUFFER0. Either or both of these can be overridden by
    command line arguments or by resources.
An xcutsel window has the following buttons:
  -  quit
- When this button is pressed, xcutsel exits. Any selections held by
      xcutsel are automatically released.
-  copy PRIMARY to 0
- When this button is pressed, xcutsel copies the current selection
      into the cut buffer.
-  copy 0 to PRIMARY
- When this button is pressed, xcutsel converts the current contents
      of the cut buffer into the selection.
The button labels reflect the selection and cutbuffer selected by
    command line options or through the resource database.
When the ``copy 0 to PRIMARY'' button is activated, the button
    will remain inverted as long as xcutsel remains the owner of the
    selection. This serves to remind you which client owns the current
    selection. Note that the value of the selection remains constant; if the
    cutbuffer is changed, you must again activate the copy button to retrieve
    the new value when desired.
Xcutsel accepts all of the standard X Toolkit command line options as
  well as the following:
  - -selection name
- This option specifies the name of the selection to use. The default is
      PRIMARY. The only supported abbreviations for this option are ``-select'',
      ``-sel'' and ``-s'', as the standard toolkit option ``-selectionTimeout''
      has a similar name.
- -cutbuffer number
- This option specifies the cut buffer to use. The default is cut buffer
    0.
This program accepts all of the standard X Toolkit resource names and classes as
  well as:
  - selection (class Selection)
- This resource specifies the name of the selection to use. The default is
      PRIMARY.
- cutBuffer (class CutBuffer)
- This resource specifies the number of the cut buffer to use. The default
      is 0.
The following instance names may be used when user configuration of the labels
  in them is desired:
  - sel-cut (class Command)
- This is the ``copy SELECTION to BUFFER'' button.
- cut-sel (class Command)
- This is the ``copy BUFFER to SELECTION'' button.
- quit (class Command)
- This is the ``quit'' button.
X(7), xclipboard(1), xterm(1), text widget documentation, individual client
  documentation for how to make a selection.
There is no way to change the name of the selection or the number of the cut
  buffer while the program is running.
Ralph R. Swick, DEC/MIT Project Athena