How to create an alias command that changes environment variable before executing an actual command

First, I'm sorry but this is kind of a "give me teh codez" question. I promise to learn from your answers, though! That means that feel free to use the Socratic method if you feel it's necessary.

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I'm currently developing (both maintenance and building new ones) multiple sites using Grails and the way it works is that it provides a commandline shell for executing various tasks.

This is all fine and well, but switching between versions is a bit of a nuisance, since it's all controlled by a single environment variable called GRAILS_HOME which is set to point to a directory such as C:\grails\grails-1.2.3\.

Now, what I would like to be able to do that instead of doing something like this:

grails create-app MyWebApp
grails list-plugins -repository=myPluginRepo
grails install-plugin myPlugin

and then noticing that I'm using the wrong version and that I have to go back, I'd rather do

g135 create-app MyWebApp
g135 list-plugins -repository=myPluginRepo
g135 install-plugin myPlugin

w开发者_开发知识库hich would immediately tell me that I'm using Grails 1.3.5.

The problem I have in creating a psh script like this is that I absolutely suck at creating scripts. I did try doing this but after about five mysterious error messages from psh itself I decided to just ask for advice.

Bonus points: If I can parameterize the alias call to specify the version (something like g[1.3.5] other params) and then append the number to the environment variable value, that'd be the most handy solution for me.

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This should do it:

Function PSGrails($ver)
    {
    $env:GRAILS_HOME='c:\grails\grails-{0}\' -f $ver
    grails $args
    }

It's just a short function that sets the variable and then executes grails as above.

Run it by specifying the version number directly after the function name:

psgrails 1.3.5 create-app MyWebApp     
psgrails 1.3.5 list-plugins -repository=myPluginRepo     
psgrails 1.3.5 install-plugin myPlugin