JLine

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JLine is an advanced console input library for Java that provides rich line editing, syntax...
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### Start a Basic Telnet Server in Java

Source: https://jline.org/docs/remote-terminals

This example demonstrates how to set up a simple Telnet server that provides a command-line interface for connected clients. It configures a local terminal, a shell provider for each client, and starts the Telnet daemon.

```java
public static void startTelnetServer() throws Exception {
    // Create a local terminal for the server
    Terminal terminal = TerminalBuilder.builder().system(true).build();

    // Create a shell provider that will be used for each client connection
    Telnet.ShellProvider shellProvider = (clientTerminal, environment) -> {
        // This code runs for each client that connects
        try {
            // Create a line reader for the client
            LineReader reader =
                    LineReaderBuilder.builder().terminal(clientTerminal).build();

            String line;
            while ((line = reader.readLine("telnet> ")) != null) {
                if ("exit".equals(line)) {
                    break;
                }
                clientTerminal.writer().println("You typed: " + line);
                clientTerminal.flush();
            }
        } catch (Exception e) {
            // Handle exceptions
        }
    };

    // Create and start the Telnet server
    Telnet telnet = new Telnet(terminal, shellProvider);
    telnet.telnetd(new String[] {
        "--port=2023", // Default is 2019
        "--ip=127.0.0.1", // Default is 127.0.0.1 (localhost only)
        "start"
    });
}
```

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

### Example Theme System Configuration File

Source: https://jline.org/docs/advanced/theme-system

Provides a concrete example of a nanorc theme system configuration file. It demonstrates the definition of token types, a mixin for whitespace, and parser configurations for comments.

```text
BOOLEAN     brightwhite
NUMBER      blue
CONSTANT    yellow
COMMENT     brightblack
DOC_COMMENT white
TODO        brightwhite,yellow
WHITESPACE  ,green
#
# mixin
#
+LINT   WHITESPACE: "[[:space:]]+" 
 WHITESPACE: "\t*"
#
# parser
```

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

### Example jnanorc Configuration

Source: https://jline.org/docs/advanced/nano-less-customization

A sample configuration file for nano/less settings and syntax highlighting.

```text
include /usr/share/nano/*.nanorc  
set tabstospaces  
set autoindent  
set tempfile  
set historylog search.log  
```

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

### Java Example: JLine Theme System

Source: https://jline.org/docs/advanced/theme-system

Demonstrates creating a terminal, line reader, theme file, syntax file, and applying custom styles to text using the JLine theme system. This example shows how to define and display various theme styles and apply them to sample code.

```java
public static void main(String[] args) {
    try {
        // Create a terminal
        Terminal terminal = TerminalBuilder.builder().system(true).build();

        // Create a line reader
        LineReader reader = LineReaderBuilder.builder().terminal(terminal).build();

        // Create a theme system file
        Path themeFile = createThemeFile();

        // Create a syntax file that uses the theme
        Path syntaxFile = createSyntaxFile();

        // Create a map for theme styles
        Map<String, AttributedStyle> themeMap = new HashMap<>();

        // Add some example styles
        themeMap.put("BOOLEAN", AttributedStyle.DEFAULT.foreground(AttributedStyle.WHITE));
        themeMap.put("NUMBER", AttributedStyle.DEFAULT.foreground(AttributedStyle.BLUE));
        themeMap.put("CONSTANT", AttributedStyle.DEFAULT.foreground(AttributedStyle.YELLOW));
        themeMap.put("COMMENT", AttributedStyle.DEFAULT.foreground(AttributedStyle.BRIGHT | AttributedStyle.BLACK));
        themeMap.put("STRING", AttributedStyle.DEFAULT.foreground(AttributedStyle.GREEN));

        // Display information about the theme system
        terminal.writer().println("Theme System Example");
        terminal.writer().println("-------------------");
        terminal.writer().println("Theme file: " + themeFile);
        terminal.writer().println("Syntax file: " + syntaxFile);
        terminal.writer().println();

        // Display the theme styles
        terminal.writer().println("Theme Styles:");
        for (Map.Entry<String, AttributedStyle> entry : themeMap.entrySet()) {
            AttributedStringBuilder asb = new AttributedStringBuilder();
            asb.append("  ");
            asb.append(entry.getKey(), entry.getValue());
            asb.append(": ");
            asb.styled(entry.getValue(), "This is styled text");
            terminal.writer().println(asb.toAttributedString());
        }
        terminal.writer().println();

        // Display a sample of styled text
        terminal.writer().println("Sample Styled Text:");
        String sampleCode = "// This is a comment\n" + "public class Example {\n" +
                "    public static void main(String[] args) {\n" +
                "        boolean flag = true;\n" +
                "        int number = 42;\n" +
                "        System.out.println(\"Hello, World!\");\n" +
                "    }\n" +
                "}\n";

        for (String line : sampleCode.split("\n")) {
            AttributedStringBuilder asb = new AttributedStringBuilder();

            // Apply simple styling based on content
            if (line.trim().startsWith("//")) {
                asb.styled(themeMap.get("COMMENT"), line);
            } else if (line.contains("true")) {
                String before = line.substring(0, line.indexOf("true"));
                String keyword = "true";
                String after = line.substring(line.indexOf("true") + 4);
                asb.append(before);
                asb.styled(themeMap.get("BOOLEAN"), keyword);
                asb.append(after);
            } else if (line.contains("42")) {
                String before = line.substring(0, line.indexOf("42"));
                String number = "42";
                String after = line.substring(line.indexOf("42") + 2);
                asb.append(before);
                asb.styled(themeMap.get("NUMBER"), number);
                asb.append(after);
            } else if (line.contains("\"Hello, World!\"")) {
                String before = line.substring(0, line.indexOf("\"Hello, World!\""));
                String string = "\"Hello, World!\"";
                String after = line.substring(line.indexOf("\"Hello, World!\"") + 15);
                asb.append(before);
                asb.styled(themeMap.get("STRING"), string);
                asb.append(after);
            } else {
                asb.append(line);
            }

            terminal.writer().println(asb.toAttributedString());
        }


```

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

### Initialize a basic confirmation prompt

Source: https://jline.org/docs/modules/console-ui

Demonstrates the setup of a Terminal and ConsolePrompt to execute a simple yes/no confirmation dialog.

```java
public static void main(String[] args) throws IOException {  
    // Create a terminal  
    Terminal terminal = TerminalBuilder.builder().build();  
  
    // Create a ConsolePrompt with the terminal  
    ConsolePrompt prompt = new ConsolePrompt(terminal);  
  
    // Get a PromptBuilder to create UI elements  
    PromptBuilder builder = prompt.getPromptBuilder();  
  
    // Create a simple yes/no prompt  
    builder.createConfirmPromp()  
            .name("continue")  
            .message("Do you want to continue?")  
            .defaultValue(ConfirmChoice.ConfirmationValue.YES)  
            .addPrompt();  
  
    try {  
        // Display the prompt and get the result  
        Map<String, PromptResultItemIF> result = prompt.prompt(builder.build());  
        System.out.println("You chose: " + result.get("continue"));  
    } catch (Exception e) {  
        e.printStackTrace();  
    } finally {  
        terminal.close();  
    }  
}  
```

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

### JLine with JCommander Example

Source: https://jline.org/docs/advanced/library-integration

This example shows how to integrate JLine with JCommander for interactive command parsing. It requires JCommander and JLine dependencies.

```java
// }  
  
// @Parameters(commandDescription = "Greet someone")  
// static class GreetCommand {  
//     @Parameter(names = {"--name", "-n"}, description = "Name to greet")  
//     String name = "World";  
// }
// @Parameters(commandDescription = "Count to a number")  
// static class CountCommand {  
//     @Parameter(names = {"--number", "-n"}, description = "Number to count to")  
//     int number = 10;  
// 
//     @Parameter(description = "Additional arguments")  
//     List<String> args = new ArrayList<>();  
```

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

### JLine POSIX Commands Registry Example

Source: https://jline.org/docs/modules/builtins

A complete example of setting up and using the PosixCommandsRegistry to execute POSIX commands within a Java application. This includes terminal setup, file creation, registry initialization, and a command loop for user interaction.

```java
public static void main(String[] args) throws Exception {
    // Create a terminal
    Terminal terminal = TerminalBuilder.builder().system(true).build();

    // Create a temporary directory for demonstration
    Path workDir = Files.createTempDirectory("jline-posix-demo");
    workDir.toFile().deleteOnExit();

    // Create some sample files
    Path file1 = workDir.resolve("sample1.txt");
    Path file2 = workDir.resolve("sample2.txt");
    Files.write(file1, "apple\nbanana\ncherry\ndate\nelderberry".getBytes(StandardCharsets.UTF_8));
    Files.write(file2, "one\ntwo\nthree\nfour\nfive".getBytes(StandardCharsets.UTF_8));

    Map<String, String> variables = new HashMap<>();

    // Create a POSIX commands registry
    PosixCommandsRegistry registry = new PosixCommandsRegistry(
            terminal.input(),
            new PrintStream(terminal.output()),
            new PrintStream(terminal.output()),
            workDir,
            terminal,
            variables::get);

    // Create a line reader
    LineReader reader = LineReaderBuilder.builder()
            .terminal(terminal)
            .parser(new DefaultParser())
            .build();

    // Print instructions
    terminal.writer().println("POSIX Commands Registry Example");
    terminal.writer().println("Working directory: " + workDir);
    terminal.writer().println();
    terminal.writer().println("Try these commands:");
    terminal.writer().println("  ls -l");
    terminal.writer().println("  cat sample1.txt");
    terminal.writer().println("  grep 'a' sample1.txt");
    terminal.writer().println("  wc sample1.txt");
    terminal.writer().println("  head -n 3 sample1.txt");
    terminal.writer().println("  sort sample1.txt");
    terminal.writer().println("  help");
    terminal.writer().println();
    terminal.writer().println("Type 'exit' to quit");
    terminal.writer().println();

    // Main command loop
    while (true) {
        String line = reader.readLine("posix> ");

        if (line.equals("exit") || line.equals("quit")) {
            break;
        }

        if (line.trim().isEmpty()) {
            continue;
        }

        try {
            if (line.equals("help")) {
                // Show available commands
                registry.printHelp();
            } else if (line.startsWith("help ")) {
                // Show help for specific command
                String command = line.substring(5).trim();
                registry.printHelp(command);
            } else {
                // Execute the command using the registry
                registry.execute(line);
            }
        } catch (Exception e) {
            terminal.writer().println("Error: " + e.getMessage());
        }

        terminal.flush();
    }

    terminal.writer().println("Goodbye!");
    terminal.close();
}
```

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

### Initialize and Run TailTipWidgets Example

Source: https://jline.org/docs/advanced/autosuggestions

Sets up a terminal, line reader with completions, and TailTipWidgets to display command suggestions and descriptions. Reads user input and processes commands until 'exit'.

```java
public static void main(String[] args) throws IOException {
    // Create a terminal
    Terminal terminal = TerminalBuilder.builder().system(true).build();

    // Create a line reader with some completions for demonstration
    LineReader reader = LineReaderBuilder.builder()
            .terminal(terminal)
            .completer(new StringsCompleter("help", "widget", "exit", "clear"))
            .build();

    // Create command descriptions for TailTipWidgets
    Map<String, CmdDesc> tailTips = new HashMap<>();

    // Description for 'help' command
    tailTips.put("help", new CmdDesc(Arrays.asList(new AttributedString("Display help information")), null, null));

    // Description for 'widget' command with options
    List<AttributedString> mainDesc = Arrays.asList(
            new AttributedString("widget -N new-widget [function-name]"),
            new AttributedString("widget -D widget ..."),
            new AttributedString("widget -A old-widget new-widget"),
            new AttributedString("widget -l [options]"));

    Map<String, List<AttributedString>> widgetOpts = new HashMap<>();
    widgetOpts.put("-N", Arrays.asList(new AttributedString("Create new widget")));
    widgetOpts.put("-D", Arrays.asList(new AttributedString("Delete widgets")));
    widgetOpts.put("-A", Arrays.asList(new AttributedString("Create alias to widget")));
    widgetOpts.put("-l", Arrays.asList(new AttributedString("List user-defined widgets")));

    tailTips.put("widget", new CmdDesc(mainDesc, null, widgetOpts));

    // Create tailtip widgets that uses description window size 5
    // and displays suggestions based on the completer
    TailTipWidgets tailtipWidgets = new TailTipWidgets(reader, tailTips, 5, TipType.COMPLETER);

    // Enable tailtip widgets
    tailtipWidgets.enable();

    // Display instructions
    terminal.writer().println("TailTip Widgets Example");
    terminal.writer().println("----------------------");
    terminal.writer().println("As you type commands, you'll see suggestions and descriptions.");
    terminal.writer().println("Try typing 'widget' to see command options and descriptions.");
    terminal.writer().println("- Type 'exit' to quit");
    terminal.writer().println();

    // Read input with tailtip widgets
    String line;
    while (true) {
        try {
            line = reader.readLine("tailtip> ");

            if (line.equalsIgnoreCase("exit")) {
                break;
            } else if (line.equalsIgnoreCase("clear")) {
                terminal.writer().print("\033[H\033[2J");
                terminal.writer().flush();
            } else {
                terminal.writer().println("You entered: " + line);
                terminal.writer().flush();
            }
        } catch (Exception e) {
            terminal.writer().println("Error: " + e.getMessage());
            terminal.writer().flush();
        }
    }

    terminal.close();
}
```

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

### Spring Shell JLine Integration Example

Source: https://jline.org/docs/advanced/library-integration

Demonstrates how JLine components are configured within a Spring Shell application. This example simulates prompt creation, command handling, and terminal setup.

```java
public static void main(String[] args) throws IOException {
    // In Spring Shell, these would be @Bean methods
    Terminal terminal = createTerminal();
    LineReader lineReader = createLineReader(terminal);

    // Simulate Spring Shell prompt provider
    String prompt = createPrompt();

    // Simulate Spring Shell command execution
    System.out.println("Spring Shell with JLine Example");
    System.out.println("Type 'help' to see available commands");
    System.out.println("Type 'exit' to quit");

    while (true) {
        String line = lineReader.readLine(prompt);

        if (line.equals("exit")) {
            break;
        } else if (line.equals("help")) {
            System.out.println("Available commands:");
            System.out.println("  help    - Show this help");
            System.out.println("  echo    - Echo a message");
            System.out.println("  hello   - Say hello");
            System.out.println("  sum     - Sum two numbers");
            System.out.println("  exit    - Exit the application");
        } else if (line.startsWith("echo")) {
            String[] parts = line.split("\\s+", 2);
            if (parts.length > 1) {
                System.out.println(parts[1]);
            } else {
                System.out.println("Usage: echo <message>");
            }
        } else if (line.startsWith("hello")) {
            String[] parts = line.split("\\s+", 2);
            String name = parts.length > 1 ? parts[1] : "World";
            System.out.println("Hello, " + name + "!");
        } else if (line.startsWith("sum")) {
            String[] parts = line.split("\\s+");
            if (parts.length == 3) {
                try {
                    int a = Integer.parseInt(parts[1]);
                    int b = Integer.parseInt(parts[2]);
                    System.out.println(a + " + " + b + " = " + (a + b));
                } catch (NumberFormatException e) {
                    System.out.println("Error: Invalid numbers");
                }
            } else {
                System.out.println("Usage: sum <a> <b>");
            }
        } else if (!line.isEmpty()) {
            System.out.println("Unknown command: " + line);
        }
    }

    System.out.println("Goodbye!");
    terminal.close();
}

// In Spring Shell, this would be a @Bean method
private static Terminal createTerminal() throws IOException {
    return TerminalBuilder.builder().system(true).build();
}

// In Spring Shell, this would be a @Bean method
private static LineReader createLineReader(Terminal terminal) {
    return LineReaderBuilder.builder()
            .terminal(terminal)
            .option(LineReader.Option.AUTO_FRESH_LINE, true)
            .option(LineReader.Option.HISTORY_BEEP, false)
            .build();
}

// In Spring Shell, this would be a @Bean method for PromptProvider
private static String createPrompt() {
    return new AttributedString("custom-shell:> ", AttributedStyle.DEFAULT.foreground(AttributedStyle.YELLOW))
            .toAnsi();
}
```

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

### Start a Basic SSH Server in Java

Source: https://jline.org/docs/remote-terminals

Initializes an SSH server with a shell consumer that processes client input via a LineReader.

```java
public static void startSshServer() throws Exception {  
    // Create a local terminal for the server  
    Terminal terminal = TerminalBuilder.builder().system(true).build();  
  
    // Create a shell consumer  
    Consumer<Ssh.ShellParams> shellConsumer = (params) -> {  
        // This code runs for each client that connects  
        try {  
            Terminal clientTerminal = params.getTerminal();  
            // Create a line reader for the client  
            LineReader reader =  
                    LineReaderBuilder.builder().terminal(clientTerminal).build();  
  
            String line;  
            while ((line = reader.readLine("ssh> ")) != null) {  
                if ("exit".equals(line)) {  
                    break;  
                }  
                clientTerminal.writer().println("You typed: " + line);  
                clientTerminal.flush();  
            }  
        } catch (Exception e) {  
            // Handle exceptions  
        }  
    };  
  
    // Create and start the SSH server  
    Ssh ssh = new Ssh(  
            shellConsumer,  
            null,  
            () -> {  
                SshServer server = SshServer.setUpDefaultServer();  
                server.setPasswordAuthenticator(  
                        (username, password, session) -> "admin".equals(username) && "password".equals(password));  
                server.setKeyPairProvider(new SimpleGeneratorHostKeyProvider());  
                return server;  
            },  
            null);  
  
    ssh.sshd(System.out, System.err, new String[] {  
        "--port=2222", // Default is 8022  
        "--ip=127.0.0.1", // Default is 127.0.0.1 (localhost only)  
        "start"  
    });  
}  
```

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

### Install Signal Handlers for Unix/Linux

Source: https://jline.org/docs/troubleshooting

Install signal handlers for common Unix signals like INT (Ctrl+C), WINCH (resize), TSTP (Ctrl+Z), and CONT (resume) for better user experience.

```java
terminal.handle(Signal.INT, signal -> {
    // Handle Ctrl+C
});

terminal.handle(Signal.WINCH, signal -> {
    // Handle terminal resize
});

terminal.handle(Signal.TSTP, signal -> {
    // Handle Ctrl+Z (suspend)
    terminal.pause();
});

terminal.handle(Signal.CONT, signal -> {
    // Handle resume from suspension
    terminal.resume();
});
```

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

### Create and Execute Commands with SystemRegistry

Source: https://jline.org/docs/modules/builtins

This example shows how to set up a SystemRegistry to handle custom commands like 'hello', 'echo', 'pwd', and 'help'. It includes parsing user input and executing registered functions. Ensure JLine libraries are included in your project.

```java
public static void main(String[] args) throws Exception {  
    // Create a terminal  
    Terminal terminal = TerminalBuilder.builder().system(true).build();  
  
    // Set up working directory  
    Path workDir = Paths.get(System.getProperty("user.dir"));  
  
    // Create a line reader  
    LineReader reader = LineReaderBuilder.builder()  
            .terminal(terminal)  
            .parser(new DefaultParser())  
            .build();  
  
    // Create a simple command registry  
    Map<String, Function<String[], Integer>> commands = new HashMap<>();  
  
    // Add commands to the registry  
    commands.put("hello", cmdArgs -> {  
        terminal.writer().println("Hello, JLine!");  
        return 0;  
    });  
  
    commands.put("echo", cmdArgs -> {  
        if (cmdArgs.length > 1) {  
            for (int i = 1; i < cmdArgs.length; i++) {  
                terminal.writer().print(cmdArgs[i]);  
                if (i < cmdArgs.length - 1) {  
                    terminal.writer().print(" ");  
                }  
            }  
            terminal.writer().println();  
        }  
        return 0;  
    });  
  
    commands.put("pwd", cmdArgs -> {  
        terminal.writer().println(workDir.toAbsolutePath());  
        return 0;  
    });  
  
    commands.put("help", cmdArgs -> {  
        terminal.writer().println("Available commands:");  
        for (String cmd : commands.keySet()) {  
            terminal.writer().println("  " + cmd);  
        }  
        return 0;  
    });  
  
    // Print instructions  
    terminal.writer().println("SystemRegistry Example");  
    terminal.writer().println("Available commands: hello, echo, pwd, help");  
    terminal.writer().println("Type 'exit' to quit");  
    terminal.writer().println();  
  
    // Main command loop  
    while (true) {  
        String line = reader.readLine("registry> ");  
  
        if (line.equals("exit") || line.equals("quit")) {  
            break;  
        }  
  
        try {  
            // Parse the line  
            ParsedLine pl = reader.getParser().parse(line, 0);  
            String[] cmdArgs = pl.words().toArray(new String[0]);  
  
            if (cmdArgs.length > 0) {  
                String command = cmdArgs[0];  
  
                // Execute the command if it exists  
                if (commands.containsKey(command)) {  
                    commands.get(command).apply(cmdArgs);  
                } else {  
                    terminal.writer().println("Unknown command: " + command);  
                    terminal.writer().println("Type 'help' for a list of commands");  
                }  
            }  
        } catch (Exception e) {  
            terminal.writer().println("Error: " + e.getMessage());  
        }  
  
        terminal.flush();  
    }  
  
    terminal.writer().println("Goodbye!");  
    terminal.close();  
}  
```

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

### Integrate POSIX ls and cd Commands with Shell

Source: https://jline.org/docs/modules/builtins

Examples demonstrating how to integrate POSIX ls and cd commands within a shell environment, utilizing CommandSession and Process objects.

```java
protected void ls(CommandSession session, Process process, String[] argv) {
    Map<String, String> colorMap = getColorMap(session);
    PosixCommands.ls(createPosixContext(session, process), argv, colorMap);
}
```

```java
protected void cd(CommandSession session, Process process, String[] argv) {
    Consumer<Path> directoryChanger = path -> session.currentDir(path);
    PosixCommands.cd(createPosixContext(session, process), argv, directoryChanger);
}
```

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

### File Operations Example with POSIX Commands

Source: https://jline.org/docs/modules/builtins

This example demonstrates how to use JLine's Builtins module to implement POSIX commands like cat, ls, grep, pwd, echo, wc, head, tail, sort, date, and clear. It requires setting up a Terminal, creating sample files, and a context for the POSIX commands. The main loop reads user input and executes the corresponding command.

```java
public static void main(String[] args) throws Exception {  
    // Create a terminal  
    Terminal terminal = TerminalBuilder.builder().system(true).build();  
  
    // Create a temporary directory for file operations  
    Path workDir = Files.createTempDirectory("jline-demo");  
    workDir.toFile().deleteOnExit();  
  
    // Variables  
    Map<String, Object> variables = new HashMap<>();  
  
    // Create some sample files  
    Path file1 = workDir.resolve("sample1.txt");  
    Path file2 = workDir.resolve("sample2.txt");  
    Files.write(  
            file1,  
            "This is sample file 1\nWith multiple lines\nFor demonstration".getBytes(StandardCharsets.UTF_8));  
    Files.write(  
            file2,  
            "This is sample file 2\nWith different content\nFor comparison".getBytes(StandardCharsets.UTF_8));  
  
    // Create a context for POSIX commands  
    PosixCommands.Context context = new PosixCommands.Context(  
            terminal.input(),  
            new PrintStream(terminal.output()),  
            new PrintStream(terminal.output()),  
            workDir,  
            terminal,  
            variables::get);  
  
    // Create a line reader  
    LineReader reader = LineReaderBuilder.builder()  
            .terminal(terminal)  
            .parser(new DefaultParser())  
            .build();  
  
    // Print instructions  
    terminal.writer().println("File Operations Example using JLine Builtins");  
    terminal.writer().println("Working directory: " + workDir);  
    terminal.writer().println("Available commands: cat, ls, grep, pwd, echo, wc, head, tail, sort, date, clear");  
    terminal.writer().println("Type 'help <command>' for command help, or 'exit' to quit");  
    terminal.writer().println();  
  
    // Main command loop  
    while (true) {  
        String line = reader.readLine("posix> ");  
  
        if (line.equals("exit") || line.equals("quit")) {  
            break;  
        }  
  
        try {  
            // Parse the command  
            String[] parts = line.split("\\s+");  
            if (parts.length == 0) continue;  
  
            String command = parts[0];  
  
            // Execute the command using PosixCommands  
            switch (command) {  
                case "cat":  
                    PosixCommands.cat(context, parts);  
                    break;  
                case "ls":  
                    PosixCommands.ls(context, parts);  
                    break;  
                case "grep":  
                    PosixCommands.grep(context, parts);  
                    break;  
                case "pwd":  
                    PosixCommands.pwd(context, parts);  
                    break;  
                case "echo":  
                    PosixCommands.echo(context, parts);  
                    break;  
                case "wc":  
                    PosixCommands.wc(context, parts);  
                    break;  
                case "head":  
                    PosixCommands.head(context, parts);  
                    break;  
                case "tail":  
                    PosixCommands.tail(context, parts);  
                    break;  
                case "sort":  
                    PosixCommands.sort(context, parts);  
                    break;  
                case "date":  
                    PosixCommands.date(context, parts);  
                    break;  
                case "clear":  
                    PosixCommands.clear(context, parts);  
                    break;  
                case "help":  
                    if (parts.length > 1) {  
                        // Show help for specific command  
                        String[] helpArgs = {parts[1], "--help"};  
                        switch (parts[1]) {  
                            case "cat":  
                                PosixCommands.cat(context, helpArgs);  
                                break;  
                            case "ls":  
                                PosixCommands.ls(context, helpArgs);  
                                break;  
                            case "grep":  
                                PosixCommands.grep(context, helpArgs);  
                                break;  
                            case "pwd":  
                                PosixCommands.pwd(context, helpArgs);  
                                break;  
                            case "echo":  
                                PosixCommands.echo(context, helpArgs);  
                                break;  
                            case "wc":  
                                PosixCommands.wc(context, helpArgs);  
                                break;  
                            case "head":  
```

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

### Configure Telnet Server Options

Source: https://jline.org/docs/remote-terminals

These examples show how to configure the Telnet server's port, IP address, check its status, and stop it using command-line arguments.

```java
// Start on a specific port and interface
telnet.telnetd(System.out, System.err, new String[]{
    "--port=2023",  // Default is 2019
    "--ip=0.0.0.0", // Default is 127.0.0.1 (localhost only)
    "start"
});

// Check server status
telnet.telnetd(System.out, System.err, new String[]{"status"});

// Stop the server
telnet.telnetd(System.out, System.err, new String[]{"stop"});
```

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

### Java Example for JLine Customization

Source: https://jline.org/docs/advanced/nano-less-customization

This Java code demonstrates the creation of `jnanorc` and `jlessrc` configuration files and a sample Java file. It shows how to initialize JLine's terminal and line reader, and provides instructions on how to use the generated configuration files with nano and less commands.

```java
public static void main(String[] args) {
    try {
        // Create a terminal
        Terminal terminal = TerminalBuilder.builder().system(true).build();

        // Create a line reader
        LineReader reader = LineReaderBuilder.builder()
                .terminal(terminal)
                .parser(new DefaultParser())
                .build();

        // Create configuration files
        Path jnanorcPath = createJnanorcFile();
        Path jlessrcPath = createJlessrcFile();

        // Display information about the configuration
        terminal.writer().println("Nano and Less Customization Example");
        terminal.writer().println("----------------------------------");
        terminal.writer().println("jnanorc file: " + jnanorcPath);
        terminal.writer().println("jlessrc file: " + jlessrcPath);
        terminal.writer().println();
        terminal.writer().println("To use nano with this configuration:");
        terminal.writer().println("  nano -rcfile " + jnanorcPath + " filename.txt");
        terminal.writer().println();
        terminal.writer().println("To use less with this configuration:");
        terminal.writer().println("  less -f " + jlessrcPath + " filename.txt");
        terminal.writer().println();

        // Create a sample file to edit
        Path sampleFile = createSampleFile();
        terminal.writer().println("Sample file created: " + sampleFile);
        terminal.writer().println();

        // In a real application, you would use the Nano or Less commands here
        // But for this example, we'll just show the configuration files

        terminal.writer().println("Press Enter to exit...");
        terminal.reader().read();

        terminal.writer().println("Goodbye!");
        terminal.writer().flush();

    } catch (Exception e) {
        e.printStackTrace();
    }
}

private static Path createJnanorcFile() throws IOException {
    String nanorcContent = "# JLine nano configuration file\n" + "set tabstospaces\n"
            + "set autoindent\n"
            + "set tempfile\n"
            + "set historylog search.log\n"
            + "\n"
            + "# Include syntax highlighting files\n"
            + "include /usr/share/nano/*.nanorc\n"
            + "\n"
            + "# Use theme system\n"
            + "theme example-theme.nanorctheme\n";

    Path nanorcFile = Paths.get("jnanorc");
    Files.write(nanorcFile, nanorcContent.getBytes());
    return nanorcFile;
}

private static Path createJlessrcFile() throws IOException {
    String lessrcContent = "# JLine less configuration file\n" + "set casesearch\n"
            + "set autoindent\n"
            + "set historylog search.log\n"
            + "\n"
            + "# Include syntax highlighting files\n"
            + "include /usr/share/nano/*.nanorc\n"
            + "\n"
            + "# Use theme system\n"
            + "theme example-theme.nanorctheme\n";

    Path lessrcFile = Paths.get("jlessrc");
    Files.write(lessrcFile, lessrcContent.getBytes());
    return lessrcFile;
}

private static Path createSampleFile() throws IOException {
    String sampleContent = "// Sample Java file for nano and less customization\n" + "\n"
            + "/**\n"
            + " * This is a sample class to demonstrate syntax highlighting\n"
            + " */\n"
            + "public class SampleClass {\n"
            + "    // Constants\n"
            + "    private static final int MAX_COUNT = 100;\n"
            + "    \n"
            + "    // Instance variables\n"
            + "    private String name;\n"
            + "    private int count;\n"
            + "    private boolean active;\n"
            + "    \n"
            + "    /**\n"
            + "     * Constructor\n"
            + "     */\n"
            + "    public SampleClass(String name) {\n"
            + "        this.name = name;\n"
            + "        this.count = 0;\n"
            + "        this.active = true;\n"
            + "    }\n"
            + "    \n"
            + "    // TODO: Add more methods\n"
            + "    \n"
            + "    /**\n"
            + "     * Main method\n"
            + "     */\n"
            + "    public static void main(String[] args) {\n"
            + "        SampleClass sample = new SampleClass(\"Test\");\n"
            + "        System.out.println(\"Created: \" + sample.name);\n"
            + "        \n"
            + "        // Loop example\n"
            + "        for (int i = 0; i < 5; i++) {\n"

```

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

### Create Example Theme File

Source: https://jline.org/docs/advanced/theme-system

Generates a nanorc theme file with various token types and styles, including mixin and parser configurations. This file defines the visual appearance of syntax highlighting.

```java
private static Path createThemeFile() throws IOException {
    String themeContent = "# Theme system configuration file\n" + "BOOLEAN     brightwhite\n" +
            "NUMBER      blue\n" +
            "CONSTANT    yellow\n" +
            "COMMENT     brightblack\n" +
            "DOC_COMMENT white\n" +
            "TODO        brightwhite,yellow\n" +
            "WHITESPACE  ,green\n" +
            "STRING      green\n" +
            "KEYWORD     brightblue\n" +
            "TYPE        cyan\n" +
            "IDENTIFIER  white\n" +
            "OPERATOR    red\n" +
            "#\n" +
            "# mixin\n" +
            "#\n" +
            "+LINT   WHITESPACE: \"[[:space:]]+$\" \\n WHITESPACE: \"\\t*\"\n" +
            "#\n" +
            "# parser\n" +
            "#\n" +
            "$LINE_COMMENT   COMMENT \\n TODO: \"(FIXME|TODO|XXX)\"\n" +
            "$BLOCK_COMMENT  COMMENT \n DOC_COMMENT: startWith=/** \n TODO: \"(FIXME|TODO|XXX)\"\n";

    Path themeFile = Paths.get("example-theme.nanorctheme");
    Files.write(themeFile, themeContent.getBytes());
    return themeFile;
}
```

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

### Implement Basic JLine Terminal Reader

Source: https://jline.org/docs/intro

A basic example showing how to initialize a terminal and line reader to process user input in a loop.

```java
public static void main(String[] args) {  
    try {  
        // Create a terminal  
        Terminal terminal = TerminalBuilder.builder().system(true).build();  
  
        // Create a line reader  
        LineReader reader = LineReaderBuilder.builder().terminal(terminal).build();  
  
        // Read lines from the user  
        while (true) {  
            String line = reader.readLine("prompt> ");  
  
            // Exit if requested  
            if ("exit".equalsIgnoreCase(line)) {  
                break;  
            }  
  
            // Echo the line back to the user  
            terminal.writer().println("You entered: " + line);  
            terminal.flush();  
        }  
  
        terminal.writer().println("Goodbye!");  
        terminal.close();  
  
    } catch (IOException e) {  
        System.err.println("Error creating terminal: " + e.getMessage());  
    }  
}  
```

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

### Launch Nano Text Editor

Source: https://jline.org/docs/modules/builtins

This example demonstrates how to launch the Nano text editor using JLine's Nano class. It configures editor options such as tab size and tab-to-space conversion before opening a specified file.

```java
public static void main(String[] args) throws IOException {  
    Terminal terminal = TerminalBuilder.builder().build();  
  
    // Configure Nano  
    Options options = Options.compile(Nano.usage()).parse(new String[] {"--tabsize=4", "--tabstospaces"});  
  
    // Launch Nano editor  
    Nano nano = new Nano(terminal, Paths.get(""), options);  
    nano.open("example.txt");  
}  
```

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

### Handle POSIX Command Execution

Source: https://jline.org/docs/modules/builtins

Example of a command loop implementation using a switch statement to route input to specific PosixCommands methods.

```java
                                PosixCommands.head(context, helpArgs);  
                                break;  
                            case "tail":  
                                PosixCommands.tail(context, helpArgs);  
                                break;  
                            case "sort":  
                                PosixCommands.sort(context, helpArgs);  
                                break;  
                            case "date":  
                                PosixCommands.date(context, helpArgs);  
                                break;  
                            case "clear":  
                                PosixCommands.clear(context, helpArgs);  
                                break;  
                            default:  
                                terminal.writer().println("Unknown command: " + parts[1]);  
                        }  
                    } else {  
                        terminal.writer()  
                                .println(  
                                        "Available commands: cat, ls, grep, pwd, echo, wc, head, tail, sort, date, clear");  
                        terminal.writer().println("Use 'help <command>' for specific command help");  
                    }  
                    break;  
                default:  
                    terminal.writer().println("Unknown command: " + command);  
                    terminal.writer().println("Type 'help' for available commands");  
            }  
        } catch (Exception e) {  
            terminal.writer().println("Error: " + e.getMessage());  
        }  
  
        terminal.flush();  
    }  
  
    terminal.writer().println("Goodbye!");  
    terminal.close();  
}
```

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

### Demonstrate JLine Display Class for Dynamic Updates

Source: https://jline.org/docs/advanced/screen-clearing

This example shows how to create and update a dynamic display using JLine's Display class. It includes a progress indicator and status updates that refresh periodically. Ensure JLine is included in your project dependencies.

```java
public static void main(String[] args) throws IOException, InterruptedException {
    Terminal terminal = TerminalBuilder.builder().build();

    // Create a Display instance
    Display display = new Display(terminal, true);

    // Create some content to display
    List<AttributedString> lines = new ArrayList<>();
    lines.add(new AttributedString("JLine Display Example"));
    lines.add(new AttributedString("==================="));
    lines.add(new AttributedString(""));
    lines.add(new AttributedString("This example demonstrates the Display class."));
    lines.add(new AttributedString("The content will update every second."));

    // Display the initial content
    display.resize(terminal.getHeight(), terminal.getWidth());
    display.update(lines, 0);

    // Update the display with a progress indicator
    for (int i = 0; i < 10; i++) {
        // Wait a bit
        TimeUnit.SECONDS.sleep(1);

        // Update the progress line
        StringBuilder progress = new StringBuilder("[");
        for (int j = 0; j < 10; j++) {
            progress.append(j <= i ? "=" : " ");
        }
        progress.append("] ").append((i + 1) * 10).append("%");

        // Update the lines
        lines.set(
                4,
                new AttributedString(
                        "Progress: " + progress, AttributedStyle.DEFAULT.foreground(AttributedStyle.GREEN)));

        // Add a status line
        if (lines.size() <= 5) {
            lines.add(new AttributedString(""));
        }
        lines.set(
                5,
                new AttributedString(
                        "Status: Processing step " + (i + 1) + " of 10",
                        AttributedStyle.DEFAULT.foreground(AttributedStyle.BLUE)));

        // Update the display
        display.update(lines, 0);
    }

    // Final update
    lines.set(
            4,
            new AttributedString(
                    "Progress: [==========] 100%", AttributedStyle.DEFAULT.foreground(AttributedStyle.GREEN)));
    lines.set(
            5, new AttributedString("Status: Complete!", AttributedStyle.DEFAULT.foreground(AttributedStyle.BLUE)));
    lines.add(new AttributedString(""));
    lines.add(new AttributedString("Press Enter to exit"));

    display.update(lines, 0);

    // Wait for Enter
    terminal.reader().read();
    terminal.close();
}
```

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

### Configure Enhanced Completion Behavior

Source: https://jline.org/docs/tab-completion

Automatically lists and menus completions with enhanced options like packing and cycling. Requires `LineReader` setup.

```java
public static void main(String[] args) throws IOException {  
    Terminal terminal = TerminalBuilder.builder().build();  
    Completer completer = new StringsCompleter("help", "exit", "list", "connect", "disconnect");  
  
    LineReader reader = LineReaderBuilder.builder()  
            .terminal(terminal)  
            .completer(completer)  
            .option(LineReader.Option.AUTO_LIST, true) // Automatically list options  
            .option(LineReader.Option.LIST_PACKED, true) // Display completions in a compact form  
            .option(LineReader.Option.AUTO_MENU, true) // Show menu automatically  
            .option(LineReader.Option.MENU_COMPLETE, true) // Cycle through completions  
            .build();  
  
    System.out.println("Type a command and press Tab to see enhanced completion behavior");  
    String line = reader.readLine("cmd> ");  
    System.out.println("You entered: " + line);  
}  

```

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

### Enable JLine History Expansion

Source: https://jline.org/docs/history

This example demonstrates how to enable history expansion, allowing the use of bash-like shortcuts such as '!!', '!n', and '!string' to recall and modify previous commands. Ensure `DISABLE_EVENT_EXPANSION` is set to false.

```java
public static void main(String[] args) throws IOException {
    Terminal terminal = TerminalBuilder.builder().build();

    // Enable history expansion
    LineReader reader = LineReaderBuilder.builder()
            .terminal(terminal)
            .option(LineReader.Option.DISABLE_EVENT_EXPANSION, false)
            .build();

    System.out.println("History expansion enabled. You can use:");
    System.out.println("!! - repeat the last command");
    System.out.println("!n - repeat command number n");
    System.out.println("!-n - repeat nth previous command");
    System.out.println("!string - repeat last command starting with string");
    System.out.println("!?string - repeat last command containing string");
    System.out.println("^string1^string2 - replace string1 with string2 in the last command");

    String line = reader.readLine("prompt> ");
    System.out.println("You entered: " + line);
}
```

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

### Implement Multi-line Input

Source: https://jline.org/docs/line-reader

This example demonstrates how to configure JLine's LineReader to support multi-line input, useful for commands with unclosed quotes or brackets. It sets a secondary prompt pattern.

```java
public String readMultiLineInput(Terminal terminal) {
    // Configure multi-line support
    LineReader reader = LineReaderBuilder.builder()
            .terminal(terminal)
            .parser(new DefaultParser())
            .variable(LineReader.SECONDARY_PROMPT_PATTERN, "%M> ")
            .build();

    System.out.println("Enter a multi-line input (e.g., with unclosed quotes or brackets):");
    // Read multi-line input
    String multiLine = reader.readLine("multi> ");

    return multiLine;
}
```

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

### Custom Completer Implementation

Source: https://jline.org/docs/tab-completion

Provides an example of creating a custom completer by implementing the Completer interface. This allows for highly specific completion logic based on the current input word. The `complete` method should populate the `candidates` list.

```java
public class CustomCompleter implements Completer {
    @Override
    public void complete(LineReader reader, ParsedLine line, List<Candidate> candidates) {
        // Get the word being completed
        String word = line.word();

        // Add completion candidates based on the current word
        if ("he".startsWith(word)) {
            candidates.add(new Candidate("help", "help", null, "Show help", null, null, true));
        }
        if ("ex".startsWith(word)) {
            candidates.add(new Candidate("exit", "exit", null, "Exit application", null, null, true));
        }

        // You can add more sophisticated logic here
        if ("co".startsWith(word)) {
            candidates.add(new Candidate("connect", "connect", null, "Connect to server", null, null, true));
        }
        if ("di".startsWith(word)) {
            candidates.add(new Candidate("disconnect", "disconnect", null, "Disconnect from server", null, null, true));
        }
    }
}
```
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