Playdemo
From OdaWiki
playdemo
After starting odamex or running odamex with +playdemo, this command plays a recorded demo
Ex. If you wanted to play a vanilla demo, you would type playdemo demotitle.lmp. If the demo is located in a different directory other than odamex, you would type playdemo C:\path\to\demo\demotitle.lmp or in *nix playdemo /home/<user>/path/to/demo/demotitle.lmp