Output data with no column headings using PowerShell

In your case, when you just select a single property, the easiest way is probably to bypass any formatting altogether:

get-qadgroupmember 'Domain Admins' | foreach { $_.Name }

This will get you a simple string[] without column headings or empty lines. The Format-* cmdlets are mainly for human consumption and thus their output is not designed to be easily machine-readable or -parseable.

For multiple properties I'd probably go with the -f format operator. Something along the lines of

alias | %{ "{0,-10}{1,-10}{2,-60}" -f $_.COmmandType,$_.Name,$_.Definition }

which isn't pretty but gives you easy and complete control over the output formatting. And no empty lines :-)

A better answer is to leave your script as it was. When doing the Select name, follow it by -ExpandProperty Name like so:

Get-ADGroupMember 'Domain Admins' | Select Name -ExpandProperty Name | out-file Admins.txt