as-update-launch-config was created to easily modify the EC2 Instance Type of an Auto Scaling Group's Launch Configuration File. The most typical use case is to change the size of instance used by an Auto Scaling Group, although as-update-launch-config can also be used to update the storage type, user-data or AMI used by a Launch Config (and hence, an Auto Scaling Group).
the above example would modify the Auto Scaling Group "my-scaling-group" to use an m1.small EC2 Instance Type with the user-data available at /home/cjohnson/web-server-user-data.txt - note that this would also use an Amazon Linux AMI by default. The three parameters -a -i and -u are required for operation, as explained in the section "Required Parameters."
## Required Parameters:
as-update-launch-config requires the following three arguments:
`-i <instance-type>` - the EC Instance Type you wish to switch use - for example -i m1.small would mean all future instances are launched as m1.small EC2 Instances.
`-b <bits>` if you specify a t1.micro, m1.small, m1.medium or c1.medium EC2 Instance Type you must specify either a 32-bit or 64-bit platform. This parameter is valid only for the t1.micro, m1.small, m1.medium and c1.medium instance types.
