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NAME
    shell - MontaukOS interactive command shell

DESCRIPTION
    The MontaukOS shell is a command interpreter launched by init
    after system services have started. It provides command
    execution, file navigation, shell variables, command chaining,
    tab completion, and command history.

    Commands are either shell builtins or external programs. When
    a command is not a builtin, the shell searches for a matching
    ELF binary and executes it as a child process.

COMMAND RESOLUTION
    When a non-builtin command is entered, the shell searches for
    a matching binary in the following order:

        1. <cwd>/<command>         (exact name, e.g. "hello.elf")
        2. <cwd>/<command>.elf
        3. 0:/os/<command>.elf
        4. 0:/os/<command>          (no extension)
        5. If on a non-zero drive, the drive root: <drive>:/<command>[.elf]

    A command containing a "/" (or an explicit drive prefix, or a
    leading "." or "/") is instead treated as a direct path and
    resolved by the kernel against the process CWD, trying the
    path as-is and then with ".elf" appended.

    The first match is spawned and the shell waits for it to exit.
    If no match is found, the shell prints:

        <command>: command not found

    Arguments after the command name are passed to the spawned
    process.

BUILTINS

   help
    Display a categorized list of available commands.

   ls [dir]
    List files in the current directory, or in the specified
    directory. Directory entries are shown with a trailing slash.
    Examples: ls, ls man, ls os

   cd [dir]
    Change the working directory. With no argument, returns to the
    logged-in user's home directory (0:/users/<user>); with /,
    returns to the drive root. Use cd .. to go up one level.
    The shell prompt reflects the current directory.
    Examples: cd os, cd .., cd

   pwd
    Print the current working directory as an absolute path
    (e.g. "0:/os").

   echo [-n] ...
    Print the arguments. -n suppresses the trailing newline.

   set [VAR=value]
    With no argument, list all shell variables (built-in and
    user-defined). With VAR=value, set a variable. With a bare
    name, print that variable's value.

   unset VAR
    Remove a user-defined shell variable.

   true / false
    Return exit status 0 / 1 without doing anything. Useful with
    && and ||.

   N:
    A bare "<number>:" (e.g. "1:") switches the current drive to
    drive N and resets the working directory to that drive's root.

   exit
    Terminate the shell process (with the last command's exit code).

SYNTAX
   Variables
    NAME=value          Set a shell variable (no leading $)
    $VAR or ${VAR}       Expand a variable's value
    $?                   Exit status of the last command
    $USER, $HOME, $PWD   Built-in dynamic variables (session user,
                        home directory, current directory)
    \$                   Escape a literal '$'

   Tilde expansion
    A leading ~ expands to the session home directory
    (0:/users/<user>) when followed by end-of-string, '/', or a
    space.

   Command chaining
    cmd1 ; cmd2          Run cmd2 unconditionally after cmd1
    cmd1 && cmd2         Run cmd2 only if cmd1 succeeded (exit 0)
    cmd1 || cmd2         Run cmd2 only if cmd1 failed (nonzero exit)

    Single and double quotes protect ;, &&, and || from being
    treated as separators.

   Comments
    A '#' outside of quotes starts a comment; the rest of the line
    is ignored.

EXTERNAL COMMANDS
    All external commands live in 0:/os/ (see COMMAND RESOLUTION).
    Where a dedicated man page exists it is noted below; run
    'man <command>' for details.

   File commands
    cat <file>          Display file contents
    edit [file]         Text editor -- see edit(1)
    copy <src> <dst>    Copy a file
    move <src> <dst>    Move/rename a file
    rm <file>           Remove a file
    touch <file>        Create an empty file

   System commands
    man <topic>         View manual pages -- see man(1)
    whoami              Print the current username
    info / mtkfetch     Show system information
    date                Show current date and time
    uptime              Show system uptime
    proclist            List running processes
    power               CPU power/thermal status (power [watch [secs]])
    clear               Clear the screen and framebuffer
    fontscale [n]       Get or set terminal font scale -- see fontscale(1)
    lua                 Lua interpreter
    tcc                 TinyCC (in-system C compiler)
    reset               Reboot the system
    shutdown            Shut down the system

   Network commands
    ping <host>         Send ICMP echo requests -- see ping(1)
    nslookup <host>     DNS lookup -- see nslookup(1)
    ifconfig            Show/set network configuration
    tcpconnect <host> <port>  Interactive TCP client
    irc                 IRC client
    dhcp                DHCP client -- see dhcp(1)
    fetch <url>         HTTP/HTTPS client (TLS 1.2) -- see fetch(1)
    wiki <title>        Wikipedia article viewer -- see wiki(1)
    httpd               HTTP server

    Network commands accept both IP addresses and hostnames.
    Hostnames are resolved via the configured DNS server.

   Bluetooth
    btlist              List connected Bluetooth devices
    btbonds              List bonded (paired) Bluetooth devices

   Software-defined radio
    sdr [freqMHz [rateHz]]  Receive and report basic signal
                        statistics from an attached RTL-SDR dongle

    GUI applications (window server programs, not run from the
    shell prompt as text commands) live under 0:/apps/, one bundle
    per app -- e.g. doom, terminal, texteditor, spreadsheet,
    wordprocessor, paint, calculator, network, bluetooth, audio,
    disks, devexplorer, procmgr, powermgr, printers, timezone,
    weather, wikipedia. There is no 0:/games/ directory.

TAB COMPLETION
    Pressing Tab completes the word under the cursor against, in
    order: executable names in 0:/os/, shell builtins, and file/
    directory entries in the current directory. A single match is
    completed inline; multiple matches are listed below the prompt.

INPUT
    The shell uses non-blocking keyboard input via SYS_GETKEY (with
    SYS_INPUT_WAIT to sleep between events) to support arrow key
    detection. Lines are limited to 255 characters.

   Editing
    Backspace       Delete character before cursor
    Tab             Tab-complete the current word
    Enter           Execute the command line

   History
    The shell stores the last 32 unique commands. Duplicate
    consecutive entries are suppressed.

    Up Arrow        Recall previous command
    Down Arrow      Recall next command (or clear line)

PROMPT
    The prompt displays the current drive and working directory:

        0:/> _              (at root of drive 0)
        0:/os> _            (in os/ directory)
        1:/> _              (at root of drive 1)

SEE ALSO
    man(1), intro(1), syscalls(2)

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