diff --git a/src/commands.hxx b/src/commands.hxx
index 92f3885..02c3147 100644
--- a/src/commands.hxx
+++ b/src/commands.hxx
@@ -2365,7 +2365,7 @@ class If: public CommandContainer {
     }
     QString description() const {
       return
-        tag()+" <variable> <cmp> <value>\n"
+        tag()+" [not] <variable> <cmp> <value>\n"
         "  <command1>\n"
         "  <command2>\n"
         "  <...>\n"
@@ -2374,7 +2374,7 @@ class If: public CommandContainer {
         "  <command4>\n"
         "  <...>\n"
         "\n\n"+
-        tag()+" <selector> -> <text>\n"
+        tag()+" [not] <selector> -> <text>\n"
         "  <command1>\n"
         "  <command2>\n"
         "  <...>\n"
@@ -2392,10 +2392,11 @@ class If: public CommandContainer {
         "The second variant checks for a text in a selector, "
         "similar to command exists. The text can be empty to just "
         "check for the existence of a selector. "
-        "There is an optional else part.";
+        "There is an optional else part. Optionally start with "
+        "not to invert the test.";
     }
     QString command() const {
-      return tag()+" "+_variable+" "+_cmp+" "+_value
+      return tag()+(_not?" not ":" ")+_variable+" "+_cmp+" "+_value
         +(_script.get()?"\n  "+_script->print().join("\n  "):"")
         +(_else.get()?"\nelse\n  "+_else->print().join("\n  "):"");
     }
@@ -2403,6 +2404,11 @@ class If: public CommandContainer {
                                    QStringList& in, QString file, int line,
                                    int indent) {
       std::shared_ptr<If> cmd(new If());
+      QRegularExpressionMatch m;
+      if (args.contains(QRegularExpression("^ *not +"), &m)) {
+        args.remove(0, m.capturedLength());
+        cmd->_not = true;
+      }
       int pos(args.indexOf(QRegularExpression("[=!.^~<>]")));
       int len(1);
       if (args.contains("->")) {
@@ -2437,8 +2443,9 @@ class If: public CommandContainer {
             break;
           }
         }
-        log(QString("evaluated expression to ")+(check?"true":"false")+": "
-            +selector+" "+_cmp+" "+value);
+        if (_not) check=!check;
+        log(QString("evaluated expression to ")+(check?"true":"false")
+            +(_not?": not ":": ")+selector+" "+_cmp+" "+value);
       } else {
         switch (_cmp[0].toLatin1()) {
           case '=': check = script->variable(_variable)==value;
@@ -2458,8 +2465,9 @@ class If: public CommandContainer {
             break;
           default:;
         }
-        log(QString("evaluated expression to ")+(check?"true":"false")+": "
-            +script->variable(_variable)+" "+_cmp+" "+value);
+        if (_not) check=!check;
+        log(QString("evaluated expression to ")+(check?"true":"false")
+            +(_not?": not ":": ")+script->variable(_variable)+" "+_cmp+" "+value);
       }
       if (check) return runScript(log, this, _script, script, frame);
       else if (_else) return runScript(log, this, _else, script, frame);
@@ -2475,6 +2483,7 @@ class If: public CommandContainer {
     QString _cmp;
     QString _value;
     std::shared_ptr<Script> _else;
+    bool _not = false;
 };
 
 class While: public CommandContainer {
@@ -2484,12 +2493,12 @@ class While: public CommandContainer {
     }
     QString description() const {
       return
-        tag()+" <variable> <cmp> <value>\n"
+        tag()+ " [not] <variable> <cmp> <value>\n"
         "  <command1>\n"
         "  <command2>\n"
         "  <...>\n"
         "\n\n"+
-        tag()+" <selector> -> <text>\n"
+        tag()+" [not] <selector> -> <text>\n"
         "  <command1>\n"
         "  <command2>\n"
         "  <...>\n"
@@ -2502,16 +2511,22 @@ class While: public CommandContainer {
         "Match allows a regular expression. "
         "The second variant checks for a text in a selector, "
         "similar to command exists. The text can be empty to just "
-        "check for the existence of a selector.";
+        "check for the existence of a selector. Optionally start with "
+        "not to invert the test.";
     }
     QString command() const {
-      return tag()+" "+_variable+" "+_cmp+" "+_value
+      return tag()+(_not?" not ":" ")+_variable+" "+_cmp+" "+_value
         +(_script.get()?"\n  "+_script->print().join("\n  "):"");
     }
     std::shared_ptr<Command> parse(Script* script, QString args,
                                    QStringList& in, QString file, int line,
                                    int indent) {
       std::shared_ptr<While> cmd(new While());
+      QRegularExpressionMatch m;
+      if (args.contains(QRegularExpression("^ *not +"), &m)) {
+        args.remove(0, m.capturedLength());
+        cmd->_not = true;
+      }
       int pos(args.indexOf(QRegularExpression("[=!.^~<>]")));
       int len(1);
       if (args.contains("->")) {
@@ -2543,8 +2558,9 @@ class While: public CommandContainer {
               break;
             }
           }
-          log(QString("evaluated expression to ")+(check?"true":"false")+": "
-              +selector+" "+_cmp+" "+value);
+          if (_not) check=!check;
+          log(QString("evaluated expression to ")+(check?"true":"false")
+              +(_not?": not ":": ")+selector+" "+_cmp+" "+value);
         } else {
           switch (_cmp[0].toLatin1()) {
             case '=': check = script->variable(_variable)==value;
@@ -2564,8 +2580,9 @@ class While: public CommandContainer {
               break;
             default:;
           }
-          log(QString("evaluated expression to ")+(check?"true":"false")+": "
-              +script->variable(_variable)+" "+_cmp+" "+value);
+          if (_not) check=!check;
+          log(QString("evaluated expression to ")+(check?"true":"false")
+              +(_not?": not ":": ")+script->variable(_variable)+" "+_cmp+" "+value);
         }
         if (check) if (!runScript(log, this, _script, script, frame)) return false;
       }
@@ -2575,6 +2592,7 @@ class While: public CommandContainer {
     QString _variable;
     QString _cmp;
     QString _value;
+    bool _not = false;
 };
 
 class TestSuite: public Command {