Você configuraria um perfil. Todos os comandos no perfil são executados toda vez que você inicia uma sessão do PowerShell. Existem perfis diferentes para usuário, máquina, etc. Conforme descrito em MSDN :
Understanding the Profiles
You can have four different profiles in Windows PowerShell. The profiles are listed in load order. The most specific profiles have precedence over less specific profiles where they apply.
%windir%\system32\WindowsPowerShell\v1.0\profile.ps1
This profile applies to all users and all shells.
%windir%\system32\WindowsPowerShell\v1.0\Microsoft.PowerShell_profile.ps1
This profile applies to all users, but only to the Microsoft.PowerShell shell.
%UserProfile%\My Documents\WindowsPowerShell\profile.ps1
This profile applies only to the current user, but affects all shells.
%UserProfile%\My Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1
This profile applies only to the current user and the Microsoft.PowerShell shell.