check if child_process has ended in node.js?

I am creating a cakefile using node.js and want to know if a child_process has ended before moving on the next one.

{exec} = require 'child_process'
 exec 'casperjs test.js', (err, stdout, stderr) ->
        err && throw err
        log stdout
        if //exec has finished
          log "finished executing"

When the callback of exec is called, the process has already been terminated. There's no need to add an additional check.

For spawn, you can bind an exit event listener.