macOS/Windows/Linux get/set sudo/admin users from Terminal

Each of macOS, Windows, and Linux has a way to get and set which users have administrative privileges (i.e. can use sudo or are in the Administrators group) from Terminal.

macOS get / set sudo users from Terminal

On macOS, the users who are sudo -capable (i.e. administrators) can be discovered from Terminal using the Directory Service command line utility dscl:

dscl . -read /Groups/admin GroupMembership

To add a user to the sudoers list, use the following command:

dscl . -append /Groups/admin GroupMembership <username>

Windows get Administrator users from Terminal

On Windows, the users who are Administrator capable can be discovered from PowerShell using:

Get-LocalGroupMember -Group "Administrators"

Query a specific user to see if they are an Administrator:

$user = "myUsername"
# put the desired username in the $user variable, then run the following command:

Get-LocalGroupMember -Group "Administrators" | Where-Object { $_.Name -like "*\$user" }

Make a user an Administrator:

Add-LocalGroupMember -Group "Administrators" -Member "myUsername"

For Windows Subsystem for Linux (WSL), use the Linux commands below.

Linux get / set sudo users from Terminal

On Linux, the users who are sudo -capable (i.e. administrators) can be discovered from Terminal using:

getent group sudo

Add a user to the sudo group (allowing them to use sudo):

sudo usermod -aG sudo <username>