demomap is the preferred command demomap demoname.dm2
i probably have a 1% chance of ever winning in duel against you
for older operating systems like win xp, there is also a program that does this for you:http://ir.tastyspleen.net/files/demoplayer.zip
copy %1 "C:\Program Files\quake2\baseq2\demos""C:\Program Files\quake2\r1q2.exe" +demomap %~n1.dm2