Although all of these can be set using streamer prefs, there may be a need to set something manually, for instance if you can't get streamer to start because you're behind a firewall. Since you can't set up the preferences unless Streamer is running, the following environment variables may come in handy!
STREAMER_MPLAYER
setenv STREAMER_MPLAYER "mpeg player command string"
MPEG audio player to use instead of MPEGA
STREAMER_HTTP_PROXY
setenv STREAMER_HTTP_PROXY "http://proxy.com" or "http://proxy.com:8000"
or "proxy.com" or "proxy.com:8080" Port number defaults to 80...
STREAMER_PLSDR
setenv STREAMER_PLSDR "data:mp3/playlists"
This is the drawer where you want to keep your Streamer playlist files.
STREAMER_MPEGAOPTS
This is the string that is fed to Streamer if it is using MPEGA as an MPEG audio player. It is the list of command line options for MPEGA that are set in Streamer Prefs. See your MPEGA documentation for details.