This is a small gist for autostarting applications with Awesome Window Manager (http://awesome.naquadah.org/) without the need to use a third party plugin like shifty. It's maybe not nice but works!

spawn_once.lua

-- {{{
--
-- Autostarting for Awesome <3.4!
-- Add this section to the end of your rc.lua
-- configuration file within ~/.config/awesome/rc.lua
--
-- If you're using Awesome 3.5 change: 
--    add_signal -> connect_signal 
--    remove_signal --> disconnect_signal
--
-- Thanks to eri_trabiccolo as well as  psychon
--
function spawn_once(command, class, tag) 
  -- create move callback
  local callback 
  callback = function(c) 
    if c.class == class then 
      awful.client.movetotag(tag, c) 
      client.remove_signal("manage", callback) 
    end 
  end 
  client.add_signal("manage", callback) 
  -- now check if not already running!     
  local findme = command
  local firstspace = findme:find(" ")
  if firstspace then
    findme = findme:sub(0, firstspace-1)
  end
  -- finally run it
  awful.util.spawn_with_shell("pgrep -u $USER -x " .. findme .. " > /dev/null || (" .. command .. ")")
end

-- use the spawn_once
spawn_once("subl", "Sublime_text", tags[1][2])
spawn_once("chromium", "Chromium", tags[1][3])
spawn_once("thunar", "Thunar", tags[1][4])
spawn_once("xchat", "Xchat", tags[1][5])
-- }}}

spawn successfully launches the program, but i cannot get it to move programs to the specified tag automatically.

tried below
spawn_once("pcmanfm", "PCManFM", tags[3][2])
spawn_once("firefox-mail.sh", "FirefoxMail", tags[1][1])

have 3 monitors, in this example pcmanfm should go to tag 2 of 3rd monitor... but they all end up in 2nd monitor tag 1 regardless of the specified tag

any idea?

$ awesome -v
awesome v3.4.15 (Never Gonna Give You Up)
• Build: Apr 28 2013 18:48:19 for x86_64 by gcc version 4.8.0 (buildd@batsu)
• D-Bus support: ✔

It doesn't work. Always run app on tag[#][1]
"#" - is number of screen

Since awesome 3.5 you must replace add_signal with connect_signal and remove_signal with disconnect_signal, then it'll work just fine.

Also, I suggest replacing the argument of spawn_with_shell:

"pgrep -u $USER -x " .. findme .. " > /dev/null || (" .. command .. ")"

with

"pgrep -u $USER -x " .. findme .. " > /dev/null || exec " .. command

This avoids spawning a subshell for the process and still works the same.

Thanks a lot! It look like it works fine now

Doesn't work properly. Same as dvd001.
So the programs run at tag 1 regardless of the specified tag.
$ awesome -v:

awesome v3.4.15 (Never Gonna Give You Up)
 • Build: Feb 17 2013 21:10:46 for x86_64 by gcc version 4.7.2 (buildd@barber)
 • D-Bus support: ✔

@kreedz Your Awesome version is pretty old...do you have a particular reason for not upgrading to v4?
If you do upgrade to >= v3.5, I have a working version in my awesome rc https://gist.github.com/silverweed/078ab193a90d2e341774#file-rc-lua-L821-L841

By the way, in recent versions of awesome you can pass rules directly to the spawn function, like so:

awful.spawn(cmd, {
    tag = mouse.screen.selected_tag,
})

If you want to emulate with_shell just pass cmd = { awful.util.shell, '-c', cmd }.

This will provide more correct behaviour, i.e. set the tag for the correct process if several are spawned simultaneously) and maybe also set the tag for all windows if the process creates more than one (I didn't test).

Also, it simplifies the code by a good deal since you don't have to manage signal handlers manually and you don't need to know the window class name in advance.