GetGroupIds returns the list of group IDs that the user is a member of, or an error.

LookupByUID is like os/user.LookupId but handles a few edge cases like gokrazy and non-cgo lookups.

LookupByUIDWithShell is like os/user.LookupId but handles a few edge cases like gokrazy and non-cgo lookups, and returns the user shell.

LookupByUsername is like os/user.Lookup but handles a few edge cases like gokrazy and non-cgo lookups.

LookupByUsernameWithShell is like os/user.Lookup but handles a few edge cases like gokrazy and non-cgo lookups, and returns the user shell.