diff --git a/hgext/blackbox.py b/hgext/blackbox.py
--- a/hgext/blackbox.py
+++ b/hgext/blackbox.py
@@ -10,9 +10,16 @@
 
 Logs event information to .hg/blackbox.log to help debug and diagnose problems.
 
-The events that get logged can be configured via the blackbox.track config key;
-this takes a list of regular expressions. As a special rule, if any item in the
-list is the string '*', everything is logged (default: '*').
+The events that get logged can be configured via the blackbox.track and
+blackbox.notrack config keys; these take a list of regular expressions. If an
+event matches an item in blackbox.notrack, it is not logged, otherwise if it
+matches an item in blackbox.track, it is logged.
+
+If blackbox.track contains an item that is just '*', blackbox.track matches
+everything (but blackbox.notrack still takes precedence).
+
+By default, blackbox.track=* and blackbox.untrack is empty, causing all events
+to be logged.
 
 Examples::
 
@@ -29,11 +36,18 @@
   # log every event starting with 'command' (including 'command' itself), and
   # everything ending with 'hook' (including 'hook' itself).
   track = command.*, .*hook
+  # explicitly ignore pythonhook
+  notrack = pythonhook
 
   [blackbox]
   track = incoming
 
   [blackbox]
+  # track = * is the default, so doesn't need to be specified here;
+  # this ignores events ending with 'hook' (and 'hook' itself)
+  notrack = .*hook
+
+  [blackbox]
   # limit the size of a log file
   maxsize = 1.5 MB
   # rotate up to N log files when the current one gets too big
@@ -90,6 +104,9 @@
 configitem('blackbox', 'track',
     default=lambda: ['*'],
 )
+configitem('blackbox', 'notrack',
+    default=lambda: [],
+)
 configitem('blackbox', 'date-format',
     default='%Y/%m/%d %H:%M:%S',
 )
@@ -111,12 +128,26 @@
             except re.error as e:
                 ui.warn(_('invalid blackbox.track setting: %s\n') % e)
                 self._active = False
+
+        self._notrackedevents = None
+        notrack = ui.configlist('blackbox', 'notrack')
+        if notrack:  # re.compile('').match matches *everything*
+            try:
+                self._notrackedevents = re.compile(br'|'.join(notrack))
+            except re.error as e:
+                # logging too much is usually less of a problem, so we just
+                # (mostly) silently accept this.
+                ui.debug('invalid blackbox.notrack setting: %s\n' % e)
+
         self._maxfiles = ui.configint('blackbox', 'maxfiles')
         self._maxsize = ui.configbytes('blackbox', 'maxsize')
         self._inlog = False
 
     def tracked(self, event):
-        return self._active and self._trackedevents.match(event)
+        return (self._active and
+                (not self._notrackedevents or
+                 not self._notrackedevents.match(event)) and
+                self._trackedevents.match(event))
 
     def log(self, ui, event, msg, opts):
         # self._log() -> ctx.dirty() may create new subrepo instance, which
diff --git a/tests/test-blackbox.t b/tests/test-blackbox.t
--- a/tests/test-blackbox.t
+++ b/tests/test-blackbox.t
@@ -396,6 +396,47 @@
   invalid blackbox.track setting: nothing to repeat
   $ cd $TESTTMP
 
+test blackbox.notrack setting
+
+(test that setting this on the commandline works, and doesn't record the 'init'
+command)
+  $ hg --config blackbox.track='*' \
+  >    --config blackbox.notrack='.*' \
+  >    init test_notrack
+  $ cd test_notrack
+  $ cat >> .hg/hgrc << EOF
+  > [blackbox]
+  > logsource = True
+  > # a rather odd way of writing 'track = command' :)
+  > track = command.*
+  > notrack = comand..*
+  > EOF
+(this should only have 'command', and not have 'commandfinish' or others)
+  $ hg blackbox
+  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000) [command]> blackbox
+  $ cd $TESTTMP
+
+invalid regex entries in blackbox.notrack cause it to be silently ignored
+
+  $ hg --config blackbox.track='command.*' \
+  >    --config blackbox.notrack=')' \
+  >    init test_notrack_invalid
+  $ cd test_notrack_invalid
+  $ cat >> .hg/hgrc << EOF
+  > [blackbox]
+  > logsource = True
+  > track = command.*
+  > # invalid: "nothing to repeat"
+  > notrack = comand..**
+  > [alias]
+  > blackboxalias = blackbox
+  > EOF
+  $ hg blackboxalias
+  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> --config 'blackbox.track=command.*' --config 'blackbox.notrack=)' init test_notrack_invalid exited 0 after * seconds (glob)
+  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000) [command]> blackboxalias
+  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000) [commandalias]> alias 'blackboxalias' expands to 'blackbox'
+  $ cd $TESTTMP
+
 #if chg
 
 when using chg, blackbox.log should get rotated correctly