Grant user sysadmin access to a SQL instance from the command line

GrantSysAdmin.sql

--::example batch file:
--pushd \\ukexchange\sysgrp\scripts\sql
--sqlcmd -S ccioaxpd05edc\axeam_train -i \\ukexchange\sysgrp\scripts\sql\grantsysadmin.sql -E -o \\ukexchange\sysgrp\scripts\sql\GrantSysAdmin.rpt 
--popd

--sql file:
-- - usage:
--   sqlcmd -S <server\instance> -i \\ukexchange\sysgrp\scripts\sql\grantsysadmin.sql -E -o \\ukexchange\sysgrp\scripts\sql\GrantSysAdmin.rpt 
use master
go
--give sys admin to the CCIT DBA team
EXEC master..sp_addsrvrolemember @loginame = N'eu\svc-dataway1', @rolename = N'sysadmin'
go
--give sys admin to myself (so I can check the script's worked & validate svc's access)
EXEC master..sp_addsrvrolemember @loginame = N'eu\sejb', @rolename = N'sysadmin'
go