AWS cli builder is a very handy site for doing just that…. building AWS cli commands. Choose from 148 services and input your required options and it will build out the command to use.
For example to start an EC2 instance, choose Computer > Elastic Computer Cloud and type start. It should provide an option for starting instances. Now enter your details such as region, instance id and output type.
More info and to access the site go here: https://awsclibuilder.com/home