with-xephyr.py

#!/usr/bin/env python

import sys, os, time
from subprocess import Popen, call

KEYBD = ("ephyr,,,xkbmodel=pc105,xkblayout=us,"
         "xkbvariant=dvorak,xkboptions=ctrl:nocaps")

USAGE = """
    Usage: %s options [command [arg...]]
      options:
        --help              : display help and exit
        --display <display> : value to bind DISPLAY to (default: :1.0)
          default: ":1.0"
        --title <title>     : value to use as the window title.
          default: "Xephyr interactive instance"
        --name <name>       : value to use as the window name.
          default: "xephyr"

      command:
        A program and arguments which will be invoked with the
        particular DISPLAY set.
        default: x-terminal-emulator

    Runs the command within a custom xephyr instance.  If the command
    is not provided, the configured x-terminal-emulator is started.
""" % (sys.argv[0],)

if any(h in sys.argv for h in ("--help", "-h")):
    print USAGE
    sys.exit(1)

options = {
    "--display" : ":1.0",
    "--title" : "Xephyr interactive instance",
    "--name" : "xephyr"
}

argvcopy = iter(sys.argv[1:])
command = []
current_key = None

for x in argvcopy:
    if current_key:
        options[current_key] = x
        current_key = None
    elif x == "--":
        command.extend(argvcopy)
    elif x.startswith("--"):
        if x not in options:
            print USAGE
            sys.exit(1)
        current_key = x
    else:
        command.append(x)
        command.extend(argvcopy)

xephyr = Popen(["Xephyr", "-keybd", KEYBD, "-ac",
                "-br", options["--display"],
                "-name", options["--name"],
                "-title", options["--title"],
                "-host-cursor", "-screen", "1600x880", "-zap",
                "-no-host-grab"])

time.sleep(0.5)

new_env = dict(os.environ)
new_env["DISPLAY"] = options["--display"]

metacity = Popen(["/usr/bin/metacity", "--sm-disable"], env=new_env)

if not command:
    command = ["x-terminal-emulator"]

try:
    res = call(command, env=new_env)
except KeyboardInterrupt:
    res = 1

metacity.terminate()
time.sleep(0.5)
xephyr.terminate()

sys.exit(res)