Web: Multiple Firefox Profiles with Linux

To run multiple instances of Firefox simultaneously, or run multiple copies with different settings/plugins, start Firefox like this:

firefox -P -no-remote

That will bring up a dialog box that lets you select a profile or create a new one.

Other Firefox command-line options:

Usage: firefox [ options ... ] [URL]
       where options include:

X11 options
  --display=DISPLAY    X display to use
  --sync               Make X calls synchronous
  --no-xshm            Don't use X shared memory extension
  --xim-preedit=STYLE
  --xim-status=STYLE
  --g-fatal-warnings   Make all warnings fatal

Mozilla options
  -height <value>      Set height of startup window to <value>.
  -h or -help          Print this message.
  -width <value>       Set width of startup window to <value>.
  -v or -version       Print Firefox version.
  -P <profile>         Start with <profile>.
  -ProfileManager      Start with ProfileManager.
  -no-remote           Open new instance, not a new window in running instance.
  -UILocale <locale>   Start with <locale> resources as UI Locale.
  -safe-mode           Disables extensions and themes for this session.
  -jsconsole           Open the Error console.
  -g or --debug        Start within /usr/bin/gdb (Must be first)