icecat man page

IceCat — GNU version of Firefox browser


icecat [Options ...] [URL]

firefox-bin [Options] [URL]


Gnuzilla IceCat is an open-source web browser, designed for standards compliance, performance and portability.

GNUzilla is the GNU version of the Mozilla suite, and GNU IceCat is the GNU version of the Firefox browser. Its main advantage is an ethical one: it is entirely free software. While the Firefox source code from the Mozilla project is free software, they distribute and recommend non-free software as plug-ins and addons.

In addition, GNU IceCat includes some privacy protection features, included in a separate addon:

Some sites refer to zero-size images on other hosts to keep track of cookies. When IceCat detects this mechanism it blocks cookies from the site hosting the zero-length image file. (It is possible to re-enable such a site by removing it from the blocked hosts list.) Other sites rewrite the host name in links redirecting the user to another site, mainly to "spy" on clicks. When this behavior is detected, IceCat shows a message alerting the user.

Origin of the name

The name IceCat was coined to show our relationship to the Mozilla Firefox browser. Ice isn't Fire and a Cat isn't a Fox, so it is clearly a different package (we don't want Mozilla blamed for our mistakes, nor cause confusion with their trademarks), but is equally clearly intimately related (of course nearly all of the work comes from the Mozilla foundation effort, so we want to give credit).


icecat is a simple shell script that will set up the environment for the actual executable, icecat-bin.


A summary of the options supported by icecat is included below.

X11 options


X display to use


Make X calls synchronous


Make all warnings fatal

IceCat options

-h, -help

Show summary of options.

-v, -version

Print IceCat version.

-P profile

Start with profile.

--profile path

Start with profile at path.


Start with migration wizard.


Start with ProfileManager.


Do not accept or send remote commands; implies --new-instance.


Open new instance, not a new window in running instance.

--UILocale locale

Start with locale resources as UI Locale.


Disables extensions and themes for this session.


Run without a GUI.


Enable remote control server.


Open a browser window.

--new-window url

Open url in a new window.

--new-tab url

Open url in a new tab.

--private-window url

Open url in a new private window.


Open Preferences dialog.

--screenshot [path]

Save screenshot to path or in working directory.

--window-size width[,height]

Width and optionally height of screenshot.

--search term

Search term with your default search engine.


Open the Browser Console.


Open the Browser Toolbox.


Spin event loop until JS debugger connects.  Enables debugging (some) application startup code paths.  Only has an effect when --jsdebugger is also supplied.


Open DevTools on initial load.

--start-debugger-server [ws:][port|path]

Start the debugger server on a TCP port or Unix domain socket path. Defaults to TCP port 6000. Use WebSocket protocol if ws: prefix is specified.

--recording file

Record drawing for a given URL.

--recording-output file

Specify destination file for a drawing recording.


Set this app as the default browser.


/usr/bin/icecat - shell script wrapping icecat
/usr/lib64/icecat/icecat-bin - icecat executable




To report a bug, please mail to


For a full list of the people who are credited with making a contribution to Mozilla, see .

Tobias Girstmair


September 20, 2018 icecat Linux User's Manual