### Bash Script Template for Knulli Datainit

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/system/knulli-datainit/datainit/system/template-custom.txt

This is a template for a custom script executed on boot and shutdown. It includes a shebang, logging setup, and conditional execution based on the script's argument.

```bash
#!/bin/bash
# This is a template for the custom script that will be launched on boot
# and shutdown, after the gamelist has finished scanning. The first line here
# is the shebang; the binary that should be called to execute it.
# Rename this file to custom.sh to enable it.
# This is an example file on changing the timezone.

# Set logfile location and filename
logfile=/tmp/scriptlog.txt
 
# Test for the condition to avoid running the script after booting has succeeded.
if test "$1" != "start"
then
  exit 0
fi

# Set the timezone.
TZ=Europe/Paris
hwclock --systz --localtime
# Write to the log file, result should be a text file with three blank lines.
echo "$1" > $logfile
echo "$1" >> $logfile

```

--------------------------------

### Patching Homebrew with DLDI Tool

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/rockchip/rk3566/fsoverlay/usr/share/drastic_aarch64/drastic_readme.txt

Example command to patch a DLDI-compliant homebrew ROM using dlditool and an R4 DLDI file.

```bash
dlditool r4ts.dldi <homebrew.nds>
```

--------------------------------

### Optimize JPGs with jpegoptim and jpegtran

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-system/roms/xash3d_fwgs/images/README.md

Strips all metadata from JPG files and then optimizes them for progressive display. Ensure you have jpegoptim and jpegtran installed.

```sh
jpegoptim --strip-all *.jpg
for f in *.jpg; do jpegtran -progressive -copy none -outfile $f -optimize $f; done
```

--------------------------------

### Example Custom Cheat File

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/rockchip/rk3566/fsoverlay/usr/share/drastic_aarch64/drastic_readme.txt

An example of a custom cheat file for Mario Kart. The cheat code consists of multiple lines of hexadecimal values.

```text
[Always Be Shyguy]+
923cdd40 0000000c
023cdd40 00000001
d2000000 00000000
94000130 fffb0000
023cdd40 0000000c
d2000000 00000000
```

--------------------------------

### Game Control Functions

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Functions to interact with the game backend. Use `reloadGamelists` to refresh game data, `emuKill` to terminate the emulator process, and `launchGame` to start a specific game.

```javascript
function reloadGamelists() { fetch('/reloadgames'); }
function emuKill() { fetch('/emukill'); }
function launchGame(game) { fetch('/launch', { method: 'POST', headers: {'Content-Type':'application/x-www-form-urlencoded'}, body: game }); }
```

--------------------------------

### Initialize WebSocket and Load Systems

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Sets up the document ready handler to fetch the list of systems and establish a WebSocket connection for real-time updates. It configures the WebSocket to parse incoming JSON data and update the display.

```javascript
var PREVDATA = null; $(document).ready(function() { fetch('/systems') .then(response => response.json()) .then(data => { showSystems(data); }); var latestOutput = document.getElementById("jumbo"); // Construct the WebSocket URL based on the current location of the web page var wsProtocol = location.protocol === 'https:' ? 'wss:' : 'ws:'; var wsHost = location.host; wsHost = wsHost.split(':')\[0\]+=":8080" var wsUrl = wsProtocol + '//' + wsHost + '/'; var ws = new WebSocket(wsUrl); ws.onmessage = function(event) { var d = event.data; if (PREVDATA != d) { var dd = JSON.parse(d); latestOutput.innerHTML = describe(dd); PREVDATA = d; } }; ws.onclose = function() { var message = { "msg": "ERROR" }; latestOutput.innerHTML = describe(message); console.log("WebSocket connection closed"); }; }); $('#myCarousel').carousel();
```

--------------------------------

### Bash Script for Game Start/Stop Events

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/system/knulli-datainit/datainit/system/scripts/template-game-start-stop.txt

This script template is designed to be executed on game watch events. It logs the event type (gameStart or gameStop) and parameters to a log file. Rename to script01.sh and make executable to use.

```bash
#!/bin/bash
# This is a template for the game start/stop custom script that will be
# launched on game watch event. The first line here
# is the shebang; the binary that should be called to execute it.
# Rename this file to script01.sh and run
# "chmod +x /userdata/system/scripts/script01.sh" to give it the executable bit
# to use it. Any valid filename is usable.
# This is an example file how Events on START or STOP can be used.

# Set logfile location and filename
logfile=/tmp/scriptlog.txt
 
# Case selection for first parameter parsed, writing to a log file on game
# watch events (starting and stopping a game):
case $1 in
    gameStart)
        echo "START" > $logfile
        echo "$@" >> $logfile
    ;;
 
    gameStop)
        echo "END" >> $logfile
    ;;
esac

```

--------------------------------

### Creating a DLDI Image File on Linux

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/rockchip/rk3566/fsoverlay/usr/share/drastic_aarch64/drastic_readme.txt

Commands to create a raw disk image file for DLDI patching. Replace <size in MB> with the desired size.

```bash
dd if=/dev/zero of=drastic_dldi.img bs=1M count=<size in MB> of=drastic_dldi.img
mkdosfs drastic_dldi.img
```

--------------------------------

### Generate Systems Report Table with jQuery

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/scripts/linux/systemsReport.html

Fetches system data from a JSON file and constructs an HTML table to display it. Use this to dynamically populate a table with system and emulator information.

```html
<!DOCTYPE html>
<html>
<head>
<title>Systems Report</title>
<style>
table {
  display: inline-table;
  border: solid 1px;
}
table th, table td {
  border: solid 1px;
}
</style>
</head>
<body>

<div id="id_table"></div>

<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
$(function() {
  $.getJSON("batocera_systemsReport.json", function(data) {
    var tab = "<table>"
    // archs
    tab += "<tr><th></th>"
    $.each(data, function(arch, arch_data) {
      tab += "<th>" + arch + "</th>"
    })
    tab += "</tr>"

    // systems
    var any_arch = ""
    $.each(data, function(arch, arch_data) {
      one_arch = arch
    })

    $.each(data[one_arch], function(system, one_arch_system_data) {
      tab += "<tr>"
      tab += "<td>" + one_arch_system_data.name + "</td>"
      $.each(data, function(arch, arch_data) {
        if(arch_data[system].red_flag) {
          tab += "<td style=\"background-color: red\">";
        } else {
          tab += "<td>";
        }
        $.each(arch_data[system].emulators, function(emulator, emulator_data) {
          $.each(emulator_data, function(x, core) {
            tab += emulator + "/" + core + "<br />";
          })
        })
        tab += "</td>"
      })
      tab += "</tr>"
    })

    tab += "</table>"
    $("#id_table").html(tab)
  })
})
</script>

</body>
</html>
```

--------------------------------

### Ramdisk Boot Configuration

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/actions/atm7039/rg35xx/uEnv.txt

Sets the operating system type to Linux and defines kernel boot arguments for ramdisk booting.

```shell
uenvcmd=setenv os_type linux;
bootargs=earlyprintk clk_ignore_unused selinux=0 init=/init  
```

--------------------------------

### Load Games via AJAX

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Fetches game data for a given system name from the '/systems/:name/games' endpoint. It parses the JSON response, sorts the games by name using `getOrder`, and then displays them using `showGames`.

```javascript
function loadGames(name) {
  var xhr = new XMLHttpRequest();
  xhr.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      var myArr = JSON.parse(this.responseText);
      myArr.sort(getOrder("name"));
      showGames(myArr);
    }
  };
  xhr.open('GET', '/systems/' + name + '/games');
  xhr.send();
}
```

--------------------------------

### Mounting a DLDI Image File

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/rockchip/rk3566/fsoverlay/usr/share/drastic_aarch64/drastic_readme.txt

Commands to mount the created DLDI image file for file transfer. Ensure the mount directory is empty.

```bash
mkdir <mount directory>
sudo mount -t vfat drastic_dldi.img -o loop <mount directory>
```

--------------------------------

### Generate System Report Table

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-system/knulli_systemsReport.html

This JavaScript code fetches system data from a JSON file and dynamically generates an HTML table to display system and emulator information, including status flags and details for each architecture. It uses jQuery for AJAX calls and DOM manipulation, and the tippy.js library for tooltips.

```javascript
$(function() {
  $.getJSON("batocera_systemsReport.json", function(data) {
    var tab = "<table>"
    // archs
    tab += "<thead>"
    tab += "<tr><th>System</th><th>Emulator</th>"
    $.each(data, function(arch, arch_data) {
      tab += "<th class=\"archname\">"
      tab += arch
      tab += "</th>"
    })
    tab += "</tr>"
    tab += "</thead>"
    // systems
    var any_arch = ""
    $.each(data, function(arch, arch_data) {
      one_arch = arch
    })
    tab += "<tbody>"
    $.each(data[one_arch], function(system, one_arch_system_data) {
      // core
      var n = 1
      $.each(one_arch_system_data["emulators"], function(one_emulator, one_arch_emulator_data) {
        $.each(one_arch_emulator_data, function(one_core, one_arch_core_data) {
          tab += "<tr>"
          if(n == 1) {
            // system
            var nb_system_cores = one_arch_system_data["nb_all_variants"]
            tab += "<td rowspan=\"" + nb_system_cores + "\"><span data-tippy-content=\"" + system + "\">

```

```javascript
            tab += one_arch_system_data.name
            tab += "</span></td>"
          }
          // core
          tab += "<td>"
          if(one_emulator == one_core) {
            tab += one_emulator
          } else {
            tab += one_emulator + "/" + one_core
          }
          tab += "</td>"
          // each arch core
          $.each(data, function(arch, arch_data) {
            $.each(arch_data[system].emulators, function(emulator, emulator_data) {
              $.each(emulator_data, function(core, core_data) {
                if(emulator == one_emulator && core == one_core) {
                  if(core_data.enabled) {
                    if(arch_data[system].red_flag) {
                      if(core_data.explanation) {
                        tab += "<td class=\"redflagexp\">"
                      } else {
                        tab += "<td class=\"redflag\">"
                      }
                    } else {
                      tab += "<td class=\"greenflag\">"
                    }
                    if(core_data.default && arch_data[system].nb_all_variants != 1) {
                      tab += "<img src=\"https://batocera.org/images/sys_default.png\" />"
                    }
                    if(core_data.explanation) {
                      tab += "<span data-tippy-content=\"" + core_data.explanation + "\"><img src=\"https://batocera.org/images/sys_ok.png\" /></span>"
                    } else {
                      tab += "<img src=\"https://batocera.org/images/sys_ok.png\" />"
                    }
                    $.each(core_data.flags, function(n, flag) {
                      tab += "<span data-tippy-content=\"" + flag + "\">

```

```javascript
                      switch(flag) {
                        case "overclocking":
                          tab += "<img src=\"https://batocera.org/images/sys_overclock.png\" />"
                          break;
                        case "slow_games":
                          tab += "<img src=\"https://batocera.org/images/sys_depends_games.png\" />"
                          break;
                        case "opengl3.0":
                          tab += "<img src=\"https://batocera.org/images/sys_opengl.png\" />"
                          break;
                        default:
                          tab += flag
                      }
                      tab += "</span>"
                    })
                    tab += "</td>"
                  } else {
                    if(arch_data[system].red_flag && !core_data.explanation) {
                      tab += "<td class=\"noreasonflag\"></td>"
                    } else {
                      tab += "<td></td>"
                    }
                  }
                }
              })
            })
          })
          tab += "</tr>"
          n++
        })
      })
    })
    tab += "</tbody>"
    tab += "</table>"
    $("#id_table").html(tab)
    tippy('\\[data-tippy-content\\]')
  })
})
```

--------------------------------

### Describe Game/System Information

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Formats and displays detailed information about the currently running game or system, including images, system name, and game name. Handles cases where no game is running or the notification service is unreachable.

```javascript
function describe(d) { var out = ""; var rlogo = null; if (d.msg) { if (d.msg == "NO GAME RUNNING") { out += '<div class="gameName" id="gameName">No game running</div>'; return (out); } if (d.msg == "ERROR") { out += '<div class="gameName" id="gameName">Notification service unreachable</div>'; return (out); } } out += '<div class="row mx-auto">'; if (d.image) { out += '<div class="col-4 float-right imgCont"><img src="' + d.image + '" class="imgArt" id="imgArt" width=64pt></div>'; } else if (d.thumbnail) { out += '<div class="col-4 float-right imgCont"><img src="' + d.thumbnail + '" class="imgArt" id="imgArt" width=64pt></div>'; } out += '<div class="col-8 sysCont">'; if (d.systemName) { var url = "/systems/" + d.systemName + "/logo"; fetch(url) .then( response => response.blob() ) .then((blob) => { const imgE = document.createElement('img'); const imgUrl = URL.createObjectURL(blob); imgE.src = imgUrl; imgE.style.height = "24pt"; const container = document.getElementById("sysName"); container.innerHTML=''; container.appendChild(imgE); }); out += '<div class="row no-gutters"><div class="col-12 sysName" id="sysName" title="">' + d.systemName +'</div></div>'; } if (d.name) { out += '<div class="row no-gutters"><div class="col-12 gameName" id="gameName" title="">' + d.name +'</div></div>'; } out += '</div></div>'; return (out); }
```

--------------------------------

### Generate System List HTML

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Generates the HTML string for displaying a list of systems, including logos and buttons, within a carousel structure. It handles pagination and dynamic content loading.

```javascript
function showSystems(arr) { var nb_sys = 3; var out = '<div class="carousel-inner">'; for (var i = 0; i < arr.length; i++) { if (i % nb_sys == 0) out += '<div class="carousel-item' + (i == 0 ? ' active' : '') + '"><div class="row mx-auto">'; if (arr[i].logo) { out += '<div class="col-4 sys-btn"><a onclick="javascript:loadGames(\''+ arr[i].name +'\')" href="#"><button type="button" class="btn btn-dark btn-block"><img class="sysLogo" style="height:48pt" src="' + arr[i].logo + '"></button></a></div>'; } else { out += '<div class="col-4 sys-btn"><a onclick="javascript:loadGames(\''+ arr[i].name +'\')" href="#"><button type="button" class="btn btn-dark btn-block">' + arr[i].fullname + '</button></a></div>'; } if ( i % nb_sys == (nb_sys - 1) ) out += '</div></div>' ; // row carousel-item } if ( i % nb_sys != (nb_sys - 1) ) out += '</div>'; // carousel-item out += '</div></div>' + // carousel-inner '<button class="carousel-control-prev btn-sm btn-outline-info" type="button" data-target="#sysCarousel" data-slide="prev">' + ' <span class="carousel-control-prev-icon" ></span>' + '</button>' + '<button class="carousel-control-next btn-sm btn-outline-info" type="button" data-target="#sysCarousel" data-slide="next">' + ' <span class="carousel-control-next-icon" ></span>' + '</button>' + '</div>'; // carousel-slide container document.getElementById("systemList").innerHTML = out; }
```

--------------------------------

### Custom Cheat File Format

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/rockchip/rk3566/fsoverlay/usr/share/drastic_aarch64/drastic_readme.txt

Defines the structure for custom cheat files. Ensure the cheat name ends with a '+' to be activated. Place these files in the appdata/DraStic/cheats directory.

```text
[Cheat Name]+
<cheat code>
```

--------------------------------

### Display Systems Carousel

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Generates HTML for a carousel of system buttons. It filters out invisible systems, then creates carousel items, each containing a row of system buttons with logos and click handlers to load games.

```javascript
function showSystems(arr) {
  const nb_sys = 6;
  var out = '<div class="carousel slide" id="sysCarousel" data-touch="true" data-interval="false" data-ride="carousel">
' + '<div class="carousel-inner">';
  var i;
  for(i = 0; i < arr.length; i++) {
    if (arr[i].visible != "true") {
      removeItem(arr, arr[i]);
    }
  }
  for(i = 0; i < arr.length; i++) {
    if ( i % nb_sys == 0 ) {
      if ( i == 0 ) out += '<div class="carousel-item active">';
      else out += '<div class="carousel-item">';
      out += '<div class="row" flex-nowrap overflow-auto>';
    }
    if (arr[i].logo) {
      out += '<div class="col-4 sys-btn"><a onclick="javascript:loadGames(\''+ arr[i].name +'\')" href="#"><button type="button" class="btn btn-dark btn-block"><img height=32pt style="max-wi
```

--------------------------------

### Display Game List

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-web-ui/web/index.html

Generates HTML for a list of games, including thumbnails, titles, metadata (genre, release date, cheevos, favorites, play count), and action buttons (Play, More Info). This function is intended to be called after fetching and processing game data.

```javascript
function showGames(arr) {
  var i;
  var out = '<div class="row mx-auto col-12 d-flex align-items-stretch justify-content-center">';
  for(i = 0; i < arr.length; i++) {
    if ( arr[i].hidden != "false") break;
    out += '<div class="card text-white bg-dark card-game">';
    if(arr[i].thumbnail) out += '<img class="card-img-top card-img-150" loading="lazy" src="' + arr[i].thumbnail + '">';
    else if(arr[i].image) out += '<img class="card-img-top card-img-150" loading="lazy" src="' + arr[i].image + '">';
    if(arr[i].marquee) out += '<img class="card-img card-title-50" loading="lazy" src="' + arr[i].marquee + '">';
    else out += '<div class="card-title text-center">' + arr[i].name + '</div>';
    out += '<div class="card-text align-items-center">';
    if (arr[i].genre) {
      out += '<p>' + arr[i].genre +'</p>';
    }
    const regex = /^\d\d\d\d/;
    if (arr[i].releasedate) {
      if (regex.test(arr[i].releasedate)) {
        out += '<p>' + arr[i].releasedate.match(regex) + '</p>';
      }
    }
    if (arr[i].cheevosHash && parseInt(arr[i].cheevosHash) != 0) {
      out += '<i class="fa fa-trophy" width=24 style="margin-left:2px; margin-right:2px"></i>';
    }
    if (arr[i].favorite == "true") {
      out += '<i class="fa fa-star" width=24 style="margin-left:2px; margin-right:2px"></i>';
    }
    if (arr[i].playcount && parseInt(arr[i].playcount) > 0) {
      out += '<p>Played ' + arr[i].playcount + ' time';
      if (parseInt(arr[i].playcount) > 1) out += 's';
      out += '</p>';
    } else {
      out += '<p>Never played</p>';
    }
    out += '</div><div class="card-footer mx-auto">';
    out += '<input type="button" class="btn btn-primary" onClick="launchGame(\'' + escapeRom(arr[i].path) + '\')" value="Play"></button>';
    if (arr[i].desc) {
      out += '<input type="button" class="btn btn-info" data-toggle="modal" data-target="#detailModal" data-desc="' + escapeHtml(arr[i].desc) + '" data-name="' + escapeHtml(arr[i].name) +'" data-thumb="' + arr[i].thumbnail + '" data-image="' + arr[i].image + '" value="More" onClick=detailFill()></button>';
    }
    out += '</div>'; // card-footer
    out += '</div>'; // card
  }
  out +='</div>'; // card-deck
  document.getElementById("gameList").innerHTML = out;
}
```

--------------------------------

### Unmounting a DLDI Image File

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/board/rockchip/rk3566/fsoverlay/usr/share/drastic_aarch64/drastic_readme.txt

Command to unmount the DLDI image file after use. This must be done before running DraStic.

```bash
sudo umount <mount directory>
```

--------------------------------

### CSS for System Report Table

Source: https://github.com/knulli-cfw/knulli-linux/blob/knulli-main/package/emulationstation/knulli-es-system/knulli_systemsReport.html

Basic CSS styling for the system report table, defining background colors, borders, and text alignment for different status indicators.

```css
body {
  background-color: #101050;
  color: #aaa;
}

table {
  display: inline-table;
  border: solid 1px;
  border-collapse: collapse;
}

table th, table td {
  border: solid 1px;
}

ul {
  list-style: none;
}

.redflag {
  text-align: center;
  background-color: #f0a;
}

.redflagexp {
  text-align: center;
  background-color: #f9d;
}

.greenflag {
  text-align: center;
}

.noreasonflag {
  background-color: #fcf;
}

.archname {
  writing-mode: vertical-rl;
  text-orientation: upright;
}
```