A mechanism for running commands in a seperate X session. Requires two files - the script to run the command through, and the xinitrc file to run the command after X starts.

xinitrc

# This file should be renamed ~/.xinitrc
# However, CAUTION: Your window manager / desktop environment may already use this file.
# In which case you should PREPEND the file with this file's contents.
# (The same applies if you have a custom xinitrc - just add this file's contents where appropriate.
#  For example, in my home .xinitrc, this clause comes after common setup (such as setting the cursor)
#  but before specifics for setting up my window manager.)
 
if [ -n "$XRUN" ]; then
    eval $XRUN
    exit
fi

xrun

#!/bin/bash
 
USAGE="$0 COMMAND {ARGS}
Run given command in a new X session.
The session should appear on the next available tty and will terminate when the command does.
"
 
if [ "$#" -lt 1 ]; then
    echo "$USAGE"
    exit 255
fi
 
# keeps looping until an available display number is found
for ((n=0;;n++)); do
    if ! [ -e "/tmp/.X11-unix/X$n" ]; then
        break
    fi
done
 
# Construct a bash command string to execute program, even if it contains spaces.
command=""
for arg in "$@"; do
    command="$command `printf %q "$arg"`"
done
 
XRUN="$command" startx -- ":$n"