Mac-mini-di-masdev:mobilehub-reference-application masdev$ echo $PATH
/Users/masdev/.rvm/gems/ruby-2.4.2/bin:/Users/masdev/.rvm/gems/ruby-2.4.2@global/bin:/Users/masdev/.rvm/rubies/ruby-2.4.2/bin:~/.npm-global/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Users/masdev/Library/Android/sdk/tools:/Users/masdev/Library/Android/sdk/platform-tools:/Users/masdev/Downloads/apache-maven-3.5.2/bin:/Users/masdev/.rvm/bin
Something like :
PATH=$PATH:<ionic-absolute-path>
<then the rest of ionic commands you run>
My two cents