elkirc

An ultra-lightweight, ELKS-first IRC client with broad OS support.

Overview

elkirc is a minimal, portable IRC client designed for resource-constrained environments while remaining fully functional on modern platforms.

Key features:

• ELKS-native: Primary target is ELKS (8086/286 with minimal RAM)
• Minimal footprint: ~1.3 KB RAM for buffers + ~100–200 KB with libc
• Portable: Builds on modern gcc (Linux, BSD, macOS, ARM, x86)
• Non-blocking I/O: Uses select() for concurrent socket + stdin handling
• Zero dependencies: No external libraries beyond POSIX/BSD sockets
• Standard IRC: Supports /connect, /nick, /join, /msg, etc.
• Color support: Optional ANSI color output for better readability (use -c flag)

Building

For modern platforms (Linux, macOS, BSD):

make

For ELKS:

make ELKS=1

This sets -D__ELKS__ to use ELKS-specific headers instead of POSIX equivalents.

Usage

elkirc [-d|--debug] [-c|--color] [-s server] [-p port] [-n nick]

Options:

• -d, --debug - Enable debug mode (show PING messages)
• -c, --color - Enable color output for better readability
• -s server - IRC server hostname (optional, can connect later with /connect)
• -p port - IRC server port (optional, defaults to 6667 if server is specified)
• -n nick - Your nickname (optional, defaults to system username if not specified)

Examples:

# Connect immediately with all options
elkirc -d -c -s irc.libera.chat -p 6667 -n alice

# Connect with minimal options (uses default port 6667 and system username)
elkirc -s irc.libera.chat

# Start without connecting (connect later with /connect)
elkirc -n alice

# Start with system username, no connection
elkirc

Behavior:

• If server and port are not provided, elkirc starts without connecting. Use /connect <server> [port] to connect later.
• If nick is not provided, elkirc uses your system username (from $USER or getpwuid()).
• Once connected, type messages directly to send to the current target (channel or user).
• Use commands (see below) prefixed with /.
• Press Ctrl+C, /quit (disconnect) or /exit to exit.

Commands

Inside elkirc, you can use the following commands:

• /connect <server> [port] or /c <server> [port] — Connect to an IRC server (port defaults to 6667)
• /nick <newnick> or /n <newnick> — Change your nickname
• /join <#channel|nick> or /j <#channel|nick> — Join a channel or switch to private messages with a user
• /leave [target] or /l [target] or /part [target] or /p [target] — Leave a channel or private conversation (leaves current target if none specified)
• /msg <nick> <message> — Send a direct message to a user or bot
• /raw <command> — Send raw IRC commands (e.g., /raw MODE #channel +o alice)
• /quit or /q — Disconnect from server (sends QUIT but doesn't exit elkirc)
• /exit or /e — Exit elkirc (sends QUIT if connected, then exits)

Note: When leaving a channel or disconnecting, the target automatically returns to your nick (instead of showing [*no-target]).

Design Notes

• Fixed buffers: All I/O uses 256-byte buffers (defined in elkirc.h) to avoid dynamic allocation
• ELKS compatibility: Conditional includes for ELKS vs. modern POSIX headers; no malloc/free in hot paths
• Non-blocking: Server messages arrive immediately without blocking user input
• PING/PONG: Automatic server PING handling to keep connection alive (hidden by default, use -d to show)

Limitations

• IPv4 only (no IPv6)
• No SSL/TLS (not feasible on ELKS)
• No channel history or backlog
• No multi-server support
• Basic RFC 1459 IRC only (no modern extensions like SASL)

License

See LICENSE file.