diff --git a/bin/bunyan b/bin/bunyan
index 0a36cef..11045dd 100755
--- a/bin/bunyan
+++ b/bin/bunyan
@@ -147,10 +147,14 @@ function printHelp() {
   util.puts("  -l, --level LEVEL");
   util.puts("                Only show messages at or above the specified level.");
   util.puts("                (See 'Log Levels' below.)");
+  util.puts("  -c, --condition CONDITION");
+  util.puts("                Run each log message through the condition");
+  util.puts("                and only show those that resolve to a truish value.");
   util.puts("");
   util.puts("Log Levels:");
   util.puts("  Either numeric values or their associated strings are valid for the");
-  util.puts("  -l --level argument.");
+  util.puts("  -l --level argument.  However, --condition scripts will see a numeric");
+  util.puts("  'level' value, not a string.");
   util.puts("");
   Object.keys(levelFromName).forEach(function(name) {
     var n = name;
@@ -196,6 +200,14 @@ function filterRecord(rec, opts)
     return false;
   }
 
+  if (opts.conditions) {
+    for (var i = 0; i < opts.conditions.length; i++) {
+      var pass = opts.conditions[i].runInNewContext(rec);
+      if (!pass)
+        return false;
+    }
+  }
+
   return true;
 }
 
@@ -276,13 +288,14 @@ function parseArgv(argv) {
     color: process.stdout.isTTY,
     outputMode: OM_PAUL,
     jsonIndent: 2,
-    level: -Infinity
+    level: -Infinity,
+    conditions: null
   };
 
   // Turn '-iH' into '-i -H', except for argument-accepting options.
   var args = argv.slice(2);  // drop ['node', 'scriptname']
   var newArgs = [];
-  var optTakesArg = {'d': true, 'o': true, 'l': true};
+  var optTakesArg = {'d': true, 'o': true, 'c': true, 'l': true};
   for (var i = 0; i < args.length; i++) {
     if (args[i].charAt(0) === "-" && args[i].charAt(1) !== '-' && args[i].length > 2) {
       var splitOpts = args[i].slice(1).split("");
@@ -353,6 +366,14 @@ function parseArgv(argv) {
         }
         parsed.level = level;
         break;
+      case "-c":
+      case "--condition":
+        var condition = args.shift();
+        parsed.conditions = parsed.conditions || []
+        var scriptName = 'bunyan-condition-'+parsed.conditions.length;
+        var script = vm.createScript(condition, scriptName);
+        parsed.conditions.push(script);
+        break
       default: // arguments
         if (!endOfOptions && arg.length > 0 && arg[0] === '-') {
           throw new Error("unknown option '"+arg+"'");
diff --git a/test/cli.test.js b/test/cli.test.js
index 89cf860..2a7ac09 100644
--- a/test/cli.test.js
+++ b/test/cli.test.js
@@ -226,3 +226,51 @@ test('--level 40', function (t) {
     });
   });
 });
+
+test('--condition "level === 10 && pid === 123"', function (t) {
+  var expect = [
+    '# levels\n',
+    '[2012-02-08T22:56:50.856Z] TRACE: myservice/123 on example.com: My message\n',
+    '\n',
+    '# extra fields\n',
+    '\n',
+    '# bogus\n',
+    'not a JSON line\n',
+    '{"hi": "there"}\n'
+  ].join('');
+  exec(BUNYAN + ' -c "level === 10 && pid === 123" corpus/all.log',
+       function (err, stdout, stderr) {
+    t.error(err);
+    t.equal(stdout, expect);
+    t.end();
+    exec(BUNYAN + ' --condition "level === 10 && pid === 123" corpus/all.log',
+         function (err, stdout, stderr) {
+      t.error(err);
+      t.equal(stdout, expect);
+      t.end();
+    });
+  });
+});
+
+// multiple
+// not sure if this is a bug or a feature.  let's call it a feature!
+test('multiple --conditions', function (t) {
+  var expect = [
+    '# levels\n',
+    '[2012-02-08T22:56:53.856Z]  WARN: myservice/1 on example.com: My message\n',
+    '\n',
+    '# extra fields\n',
+    '\n',
+    '# bogus\n',
+    'not a JSON line\n',
+    '{"hi": "there"}\n'
+  ].join('');
+  t.end();
+  exec(BUNYAN + ' test/corpus/all.log ' +
+       '-c "if (level === 40) pid = 1; true" ' +
+       '-c "pid === 1"', function (err, stdout, stderr) {
+    t.error(err);
+    t.equal(stdout, expect);
+    t.end();
+  });
+});