Set default server in powershell for AD related commands

Recently my powershell scripts require to explicitly say which domain I want to connect to. Is it necessary to write this for each command? Or can I set it somehow once in the beginning of the script.

Instead of Get-ADUser -Server server otherparameters

could I write in the beginning something like Set-default server to connect to ?

Is it necessary to write this for each command?

No!

You can specify a default parameter value for a parameter belonging to one or more cmdlets by assigning it to the $PSDefaultParameterValues automatic variable:

$PSDefaultParameterValues['*-AD*:Server'] = 'mydc.mydomain.tld'

Any cmdlet you subsequently invoke that matches the *-AD* pattern by name and has a -Server parameter will now implicitly have 'mydc.mydomain.tld' bound to the -Server parameter unless an argument is explicitly passed.

In other words: next time you invoke Get-ADUser rsterba, PowerShell now calls Get-ADUser rsterba -Server 'mydc.mydomain.tld' instead.

For more information about $PSDefaultParameterValues and how it works, see the about_Parameters_Default_Values help topic

If you want to pass the same argument but selectively, use partial splatting to avoid re-typing -Server ...:

# define target DC in a hashtable
$srv = @{ Server = 'mydc.mydomain.tld'}
# ... it doesn't have to be a hardcoded value
$srv = @{ Server = (Get-ADDomainController -Discover -Service PrimaryDC).HostName}

# `@srv` will expand to `-Server <DC hostname>`
Get-ADUser <# other parameters #> @srv

# ... but it no longer applies by default, so omitting it restore the original behavior
Get-ADUser <# other parameters #>