Update README

Solves #8 and !2

README.md

@@ -28,19 +28,35 @@ ESC when pressed alone is quite handy, specially in vi.
 ```
 $ git clone git@gitlab.com:interception/linux/plugins/caps2esc.git
 $ cd caps2esc
-$ mkdir build
-$ cd build
-$ cmake ..
-$ make
+$ cmake -B build -DCMAKE_BUILD_TYPE=Release
+$ cmake --build build
 ```
 
 ## Execution
 
+```
+caps2esc - transforming the most useless key ever in the most useful one
+
+usage: caps2esc [-h] [-m mode]
+
+options:
+    -h        show this message and exit
+    -m mode   0: default
+                - caps as esc/ctrl
+                - esc as caps
+              1: minimal
+                - caps as esc/ctrl
+              2: useful on 60% layouts
+                - caps as esc/ctrl
+                - esc as grave accent
+                - grave accent as caps
+```
+
 `caps2esc` is an [_Interception Tools_][interception-tools] plugin. A suggested
 `udevmon` job configuration is:
 
 ```yaml
-- JOB: "intercept -g $DEVNODE | caps2esc | uinput -d $DEVNODE"
+- JOB: intercept -g $DEVNODE | caps2esc | uinput -d $DEVNODE
   DEVICE:
     EVENTS:
       EV_KEY: [KEY_CAPSLOCK, KEY_ESC]
@@ -50,11 +66,37 @@ $ make
 For more information about the [_Interception Tools_][interception-tools], check
 the project's website.
 
+## Mouse button support
+
+After _Interception Tools_ 0.3, `caps2esc` can work with mouse clicks. An
+example configuration taken from my laptop:
+
+```yaml
+SHELL: [zsh, -c]
+---
+- JOB: mux -c caps2esc
+- JOB:
+    - intercept -g $DEVNODE | mux -o caps2esc
+    - mux -i caps2esc | caps2esc | uinput -d $DEVNODE
+  DEVICE:
+    LINK: /dev/input/by-path/platform-i8042-serio-0-event-kbd
+- JOB:
+    - intercept $DEVNODE | mux -o caps2esc
+  DEVICE:
+    LINK: /dev/input/by-path/platform-i8042-serio-4-event-mouse
+```
+
+For more information on the topic, check the [_Interception Tools_
+README][interception-tools] about usage of the `mux` tool and device specific
+setups.
+
 ## Installation
 
-I'm maintaining an Archlinux package on AUR:
+It's available from [community](https://archlinux.org/packages/community/x86_64/interception-caps2esc/):
 
-- <https://aur.archlinux.org/packages/interception-caps2esc>
+```
+$ pacman -S interception-caps2esc
+```
 
 I don't use Ubuntu and recommend Archlinux instead, as it provides the AUR, so I
 don't maintain PPAs. For more information on Ubuntu/Debian installation check

caps2esc.c

@@ -18,6 +18,28 @@ capslock_repeat = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 2},
 syn             = {.type = EV_SYN, .code = SYN_REPORT,   .value = 0};
 // clang-format on
 
+void print_usage(FILE *stream, const char *program) {
+    // clang-format off
+    fprintf(stream,
+            "caps2esc - transforming the most useless key ever in the most useful one\n"
+            "\n"
+            "usage: %s [-h] [-m mode]\n"
+            "\n"
+            "options:\n"
+            "    -h        show this message and exit\n"
+            "    -m mode   0: default\n"
+            "                - caps as esc/ctrl\n"
+            "                - esc as caps\n"
+            "              1: minimal\n"
+            "                - caps as esc/ctrl\n"
+            "              2: useful on 60%% layouts\n"
+            "                - caps as esc/ctrl\n"
+            "                - esc as grave accent\n"
+            "                - grave accent as caps\n",
+            program);
+    // clang-format on
+}
+
 int equal(const struct input_event *first, const struct input_event *second) {
     return first->type == second->type && first->code == second->code &&
            first->value == second->value;
@@ -32,7 +54,20 @@ void write_event(const struct input_event *event) {
         exit(EXIT_FAILURE);
 }
 
-int main(void) {
+int main(int argc, char *argv[]) {
+    int opt, mode = 0;
+    while ((opt = getopt(argc, argv, "hm:")) != -1) {
+        switch (opt) {
+            case 'h':
+                return print_usage(stdout, argv[0]), EXIT_SUCCESS;
+            case 'm':
+                mode = optarg[0] - '0';
+                continue;
+        }
+
+        return print_usage(stderr, argv[0]), EXIT_FAILURE;
+    }
+
     int capslock_is_down = 0, esc_give_up = 0;
     struct input_event input;
 
@@ -77,8 +112,23 @@ int main(void) {
             continue;
         }
 
+        switch (mode) {
+            case 0:
                 if (input.code == KEY_ESC)
                     input.code = KEY_CAPSLOCK;
+                break;
+            case 2:
+                switch (input.code) {
+                    case KEY_ESC:
+                        input.code = KEY_GRAVE;
+                        break;
+                    case KEY_GRAVE:
+                        input.code = KEY_CAPSLOCK;
+                        break;
+                }
+                break;
+        }
+
         write_event(&input);
     }
 }