Script used to easily change grails version on the commandline in OS X

setgrails.groovy

#!/usr/bin/env groovy

/* setgrails: Script used to easily change grails version on the commandline in OS X
 * 
 * My setup:
 * /User/leo/Apps/grails		Folder where all versions of grails are installed
 * /User/leo/Apps/grails/grails		A symlink pointing to the version of grails I'm currently using
 * /User/leo/Apps/grails-1.3.1		One of the installed versions
 *
 * in ~/.profile
 * export GRAILS_HOME=/User/leo/Apps/grails/grails
 * export PATH=$GRAILS_HOME/bin:$PATH
 */

// Validate args
assert args.size() == 1
def version = args[0]
assert version ==~ /(?:\d+\.?)+/

def grailsInstallDir = new File('/Users/leo/Apps/grails')
def currentGrails = new File(grailsInstallDir, 'grails')
def grailsHome = new File(grailsInstallDir, "grails-$version")

// Check that all needed folders exist
assert grailsInstallDir.exists()
assert currentGrails.exists()
assert grailsHome.exists()

// Remove old symlink and link to the choosen grails version
currentGrails.delete()
def proc = ['ln', '-s', grailsHome.absolutePath, currentGrails.absolutePath].execute()
proc.consumeProcessOutput System.out, System.err

println "GRAILS set to $version"