is the command the same to bring up the consol for hl2?
yes. however you'll need to go into the options, under the keyboard tab IIRC and choose "enable console" or something like that. in game, press tilde.
now, cl_showfps 1 and cl_showfps 2 (the difference is that one is the smooth fps and the other is not) don't show up everytime, if you want them, you'll need to put them in your autoexec.cfg file. however i dont recommend those since the readout is REALLY small.
i suggest messing with net_graph (use 1, 2, 3, depending on what you like) and net_graphpos (1 = right 2 = middle 3 = left). that displays the FPS bigger along with useful info like choke and loss, plus it's bigger. furthermore, you don't need to add it to your autoexec file; it stays forever.