2 examples for firefox

{{ score }} 
  # open firefox profile manager
firefox -P

# open a given profile
firefox -P nameofmyprofile

# open another profile without shutting down the first one
firefox -P nameofmyotherprofile -no-remote
  Submitted by anonymous user almost 12 years ago [permalink]
{{ score }} 
  # Launch Firefox in private browsing mode 
firefox -private-window
  Submitted by anonymous user almost 10 years ago [permalink]