Tkinter-based solution mentioned in Cameron Laird's answer:

import Tkinter
root = Tkinter.Tk()
print(root.selection_get(selection="CLIPBOARD"))

Replace "CLIPBOARD" with "PRIMARY" to get PRIMARY selection instead.

Also see this answer.

python-xlib solution, based on PrintSelection() and python-xlib/examples/get_selection.py

from Xlib import X, display as Xdisplay

def property2str(display, prop):
    if prop.property_type == display.get_atom("STRING"):
        return prop.value.decode('ISO-8859-1')
    elif prop.property_type == display.get_atom("UTF8_STRING"):
        return prop.value.decode('UTF-8')
    else:
        return "".join(str(c) for c in prop.value)

def get_selection(display, window, bufname, typename):
    bufid = display.get_atom(bufname)
    typeid = display.get_atom(typename)
    propid = display.get_atom('XSEL_DATA')
    incrid = display.get_atom('INCR')

    window.change_attributes(event_mask = X.PropertyChangeMask)
    window.convert_selection(bufid, typeid, propid, X.CurrentTime)
    while True:
        ev = display.next_event()
        if ev.type == X.SelectionNotify and ev.selection == bufid:
            break

    if ev.property == X.NONE:
        return None # request failed, e.g. owner can't convert to target format type
    else:
        prop = window.get_property(propid, X.AnyPropertyType, 0, 2**31-1, 1)

        if prop.property_type == incrid:
            result = ""
            while True:
                while True:
                    ev = display.next_event()
                    if ev.type == X.PropertyNotify and ev.atom == propid and ev.state == X.PropertyNewValue:
                        break

                prop = window.get_property(propid, X.AnyPropertyType, 0, 2**31-1, 1)
                if len(prop.value) == 0:
                    break

                result += property2str(display, prop)
            return result
        else:
            return property2str(display, prop)

display = Xdisplay.Display()
window = display.screen().root.create_window(0,0, 1,1, 0, X.CopyFromParent)
print( get_selection(display, window, "CLIPBOARD", "UTF8_STRING") or \
       get_selection(display, window, "CLIPBOARD", "STRING") )

For Linux you could use your original code using the xclip utility instead of pbpaste/pbcopy:

import subprocess

def getClipboardData():
    p = subprocess.Popen(['xclip','-selection', 'clipboard', '-o'], stdout=subprocess.PIPE)
    retcode = p.wait()
    data = p.stdout.read()
    return data

def setClipboardData(data):
    p = subprocess.Popen(['xclip','-selection','clipboard'], stdin=subprocess.PIPE)
    p.stdin.write(data)
    p.stdin.close()
    retcode = p.wait()

xclip's parameters:

• -selection clipboard: operates over the clipboard selection (X Window have multiple "clipboards"
• -o: read from desired selection

You should notice that this solution operates over binary data. To storing a string you can use:

setClipboardData('foo'.encode())

And lastly if you are willing to use your program within a shell piping look my question about a issue.

You can use an external program, xsel:

from subprocess import Popen, PIPE
p = Popen(['xsel','-pi'], stdin=PIPE)
p.communicate(input='Hello, World')

With xsel, you can set the clipboard you want to work on.

• -p works with the PRIMARY selection. That's the middle click one.
• -s works with the SECONDARY selection. I don't know if this is used anymore.
• -b works with the CLIPBOARD selection. That's your Ctrl + V one.

Read more about X's clipboards here and here.

A quick and dirty function I created to handle this:

def paste(str, p=True, c=True):
    from subprocess import Popen, PIPE

    if p:
        p = Popen(['xsel', '-pi'], stdin=PIPE)
        p.communicate(input=str)
    if c:
        p = Popen(['xsel', '-bi'], stdin=PIPE)
        p.communicate(input=str)

paste('Hello', False)    # pastes to CLIPBOARD only
paste('Hello', c=False)  # pastes to PRIMARY only
paste('Hello')           # pastes to both

You can also try pyGTK's clipboard :

import pygtk
pygtk.require('2.0')
import gtk

clipboard = gtk.clipboard_get()

clipboard.set_text('Hello, World')
clipboard.store()

This works with the Ctrl + V selection for me.