diff --git a/common/content/abbreviations.js b/common/content/abbreviations.js
index 238ced70..dc22d8cc 100644
--- a/common/content/abbreviations.js
+++ b/common/content/abbreviations.js
@@ -296,25 +296,19 @@ var Abbreviations = Module("abbreviations", {
             commands.add([ch + "una[bbreviate]"],
                 "Remove an abbreviation" + modeDescription,
                 function (args) {
-                    let lhs = args.literalArg;
-                    if (!lhs)
-                        return dactyl.echoerr("E474: Invalid argument");
-                    if (!args["-group"].remove(modes, lhs))
+                    util.assert(args.bang ^ !!args[0], "Argument or ! required");
+
+                    if (args.bang)
+                        args["-group"].clear(modes);
+                    else if (!args["-group"].remove(modes, lhs))
                         return dactyl.echoerr("E24: No such abbreviation");
                 }, {
-                    argCount: "1",
+                    argCount: "?",
+                    bang: true,
                     completer: function (context) completion.abbreviation(context, modes, args["-group"]),
                     literal: 0,
                     options: [contexts.GroupFlag("abbrevs")]
                 });
-
-            commands.add([ch + "abc[lear]"],
-                "Remove all abbreviations" + modeDescription,
-                function (args) { args["-group"].clear(modes); },
-                {
-                    argCount: "0",
-                    options: [contexts.GroupFlag("abbrevs")]
-                });
         }
 
         addAbbreviationCommands([modes.INSERT, modes.COMMAND_LINE], "", "");
diff --git a/common/content/mappings.js b/common/content/mappings.js
index cc48bb3e..804febb0 100644
--- a/common/content/mappings.js
+++ b/common/content/mappings.js
@@ -575,50 +575,31 @@ var Mappings = Module("mappings", {
                 function (args) { map(args, true); },
                 opts);
 
-            commands.add([ch + "mapc[lear]"],
-                "Remove all mappings" + modeDescription,
-                function (args) {
-                    util.assert(args["-group"].modifiable,
-                                "Cannot change mappings in the builtin group");
-
-                    let mapmodes = array.uniq(args["-modes"].map(findMode));
-                    mapmodes.forEach(function (mode) {
-                        args["-group"].clear(mode);
-                    });
-                },
-                {
-                    argCount: "0",
-                    options: [
-                        contexts.GroupFlag("mappings"),
-                        update({}, modeFlag, {
-                            names: ["-modes", "-mode", "-m"],
-                            type: CommandOption.LIST,
-                            description: "Remove all mappings from the given modes",
-                            default: mapmodes || ["n", "v"]
-                        })
-                    ]
-                });
-
             commands.add([ch + "unm[ap]"],
                 "Remove a mapping" + modeDescription,
                 function (args) {
                     util.assert(args["-group"].modifiable,
                                 "Cannot change mappings in the builtin group");
 
+                    util.assert(args.bang ^ !!args[0], "Argument or ! required");
+
                     let mapmodes = array.uniq(args["-modes"].map(findMode));
 
-                    let found = false;
-                    for (let [, mode] in Iterator(mapmodes)) {
-                        if (args["-group"].has(mode, args[0])) {
+                    let found = 0;
+                    for (let mode in values(mapmodes))
+                        if (args.bang)
+                            args["-group"].clear(mode);
+                        else if (args["-group"].has(mode, args[0])) {
                             args["-group"].remove(mode, args[0]);
-                            found = true;
+                            found++;
                         }
-                    }
-                    if (!found)
+
+                    if (!found && !args.bang)
                         dactyl.echoerr("E31: No such mapping");
                 },
                 {
-                    argCount: "1",
+                    argCount: "?",
+                    bang: true,
                     completer: opts.completer,
                     options: [
                         contexts.GroupFlag("mappings"),
diff --git a/common/modules/commands.jsm b/common/modules/commands.jsm
index 1ad61eff..87fdcb56 100644
--- a/common/modules/commands.jsm
+++ b/common/modules/commands.jsm
@@ -622,6 +622,7 @@ var Commands = Module("commands", {
          * Displays a list of user-defined commands.
          */
         list: function list() {
+            const { commandline, completion } = this.modules;
             function completerToString(completer) {
                 if (completer)
                     return [k for ([k, v] in Iterator(config.completers)) if (completer == completion.closure[v])][0] || "custom";
@@ -631,7 +632,7 @@ var Commands = Module("commands", {
             if (!this.userHives.some(function (h) h._list.length))
                 dactyl.echomsg("No user-defined commands found");
             else
-                modules.commandline.commandOutput(
+                commandline.commandOutput(
                     <table>
                         <tr highlight="Title">
                             <td/>
@@ -1487,13 +1488,22 @@ var Commands = Module("commands", {
                     .flatten().array
             });
 
-        commands.add(["comc[lear]"],
-            "Delete all user-defined commands",
+        commands.add(["delc[ommand]"],
+            "Delete the specified user-defined command",
             function (args) {
-                args["-group"].clear();
-            },
-            {
-                argCount: "0",
+                util.assert(args.bang ^ !!args[0], "Argument or ! required");
+                let name = args[0];
+
+                if (args.bang)
+                    args["-group"].clear();
+                else if (args["-group"].get(name))
+                    args["-group"].remove(name);
+                else
+                    dactyl.echoerr("E184: No such user-defined command: " + name);
+            }, {
+                argCount: "?",
+                bang: true,
+                completer: function (context, args) modules.completion.userCommand(context, args["-group"]),
                 options: [contexts.GroupFlag("commands")]
             });
 
@@ -1506,21 +1516,6 @@ var Commands = Module("commands", {
                 literal: 0
             });
 
-        commands.add(["delc[ommand]"],
-            "Delete the specified user-defined command",
-            function (args) {
-                let name = args[0];
-
-                if (args["-group"].get(name))
-                    args["-group"].remove(name);
-                else
-                    dactyl.echoerr("E184: No such user-defined command: " + name);
-            }, {
-                argCount: "1",
-                completer: function (context, args) modules.completion.userCommand(context, args["-group"]),
-                options: [contexts.GroupFlag("commands")]
-            });
-
         dactyl.addUsageCommand({
             name: ["listc[ommands]", "lc"],
             description: "List all Ex commands along with their short descriptions",
diff --git a/common/modules/styles.jsm b/common/modules/styles.jsm
index dffdcfd2..e438d979 100644
--- a/common/modules/styles.jsm
+++ b/common/modules/styles.jsm
@@ -636,14 +636,18 @@ var Styles = Module("Styles", {
             {
                 name: ["dels[tyle]"],
                 desc: "Remove a user style sheet",
-                action: function (sheet) sheet.remove()
+                action: function (sheet) sheet.remove(),
             }
         ].forEach(function (cmd) {
             commands.add(cmd.name, cmd.desc,
                 function (args) {
+                    dactyl.assert(args.bang ^ !!(args[0] || args[1] || args["-name"] || args["-index"]),
+                                  "Argument or ! required");
+
                     args["-group"].find(args["-name"], args[0], args.literalArg, args["-index"])
                                   .forEach(cmd.action);
                 }, {
+                    bang: true,
                     completer: function (context, args) {
                         let uris = util.visibleURIs(window.content);