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jj irc

A file-based IRC client.

Image of jjp sample output

Index

Concepts

jj irc is an evolution of the ii(1) IRC client. It is a suite of multiple smaller programs which together form a full-fledged IRC client. It consists of the following three (interchangeable) core components:

  1. jjd - The daemon. It does the bare minimum like connecting to the IRC server and reading user input from a named pipe (fifo). It spawns a child and forwards all user and IRC messages to it. Text printed by the child is directly forwarded to the IRC server. Written in C.
  2. jjc - The client. Gets spawned as child of jjd and handles the more typical IRC client things. Written in AWK.
  3. jjp - Pretty prints log files from disk or stdin. Written in AWK.

jj tries to stay true to the UNIX philosophy, which says:

Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface.

The IRC output is saved in various log files, user input is read via a named pipe and certain events are handled by external tools.

Log files being the IRC client makes it possible to use the systems text mangling utilities on them (think grep(1)) and it automatically adds a nice separation between the back-end (jjq(1)) and front-end. The front-end can easily be stopped and restarted without affecting the back-end. Building a front-end could be as easy as tail -f and some tmux(1) usage. Or it could be a complex log parser, which colors messages, right aligns nicknames and more. Want to filter out join messages? Use grep(1) in the pipeline. Scrollback and search? tmux(1)!

Reading input via a named pipe makes it possible to script the input side of the front-end. For instance, want to use your editor to write and send IRC messages? No problem, you can do that!

Common tasks, e.g. auto-joining channels after connecting to an IRC server, are not handled by jjc(1) itself, but instead are delegated to external programs (usually shell scripts). That gives the user a lot of freedom and power in terms of scriptability. To stay with the channel auto-join example: After successfully connecting, jjc(1) runs irc_on_connect if it's in PATH. That program can of course be written in your favorite languange. It could check the current host and, depending on server, join different channels, auth with services etc. The irc_on_highlight script could be used to send desktop/push notifications. The irc_on_join script could be used to automatically open new windows in tmux(1), whenever a channel is joined. See Hooks for more details.

Dependencies

Nothing but a C compiler and awk(1).

Supported AWK implementations are gawk, nawk, mawk & busybox awk. The original awk described in "The AWK Programming Language" is not working.

Installation

As root user:

make
make install

or as unpriviliged user:

make
make PREFIX=~/.local install
PATH=~/.local/bin:$PATH

Usage

None of the programs have any options and instead are controlled entirely by environment variables. To change the defaults, it makes sense to add the desired changes to ~/.profile or similar, so that they don't have to be entered manually for every jjd(1) invocation. For the full list of variables, see the Environment Variables section.

Connecting to a Server

To connect to an IRC server, simply run:

jjd

Or:

IRC_HOST=irc.rizon.net jjd

By default jjd(1) connects to irc.libera.chat, using the current user as nickname and creates the directory "irc.libera.chat" in the current working directory. Located in that directory will be the various log files and the named pipe for input. For more information, see Directory Structure and Input Commands.

Printing a Log

To save some typing, change into the directory of that new connection:

cd irc.libera.chat

To display the IRC output, the most basic would be to simply run:

cat server.log

cat could also be replaced with jjp for prettier output.

Joining And Sending to a Channel

To join a channel and say something in it, run:

echo 'join #jj' >in

And then:

echo 'msg #jj Hello, World!' >in

The output of that channel can then be read from channels/\#jj.log.

Because nobody wants to type that full command for every message, a simple loop can make this more convenient:

while IFS= read -r line; do printf 'msg #jj %s\n' "$line"; done

See Examples for a more elaborate version of that input-loop.

Directory Structure

The following shows a typical channel structure tree created by jj irc.

irc.libera.chat/
├── channels/
│   ├── #jj.log
│   └── nickserv.log
├── in
├── motd
└── server.log

server.log is where all non-channel specific messages go. Instead of spamming server.log with the servers message of the day, every time the user connects, it is instead written to the file called motd. The file named in is a named pipe, used for sending messages to the IRC server. The channels directory contains log files of channels and private messages.

Note: The directories and the in-fifo are created by jjd(1), while all the logfiles are created by jjc(1).

Input Commands

These are the input commands supported by jjc(1). All commands are case-insensitive. "target" is a channel or a nickname. Parameters in square brackets are optional.

Command Parameter 1 Parameter 2 Parameter 3 Description
action target message n/a Send an action message to a user or channel.
me target message n/a An alias for action.
away [away text] n/a n/a Mark yourself as away. Without parameters it unsets away.
invite nickname channel n/a Invite a user to a channel.
join channel1[,channel2]... [password1[,password2]...] n/a Join channels.
kick channel nickname [reason] Kick a user from a channel.
list n/a n/a n/a Print a list of all currently open channels (including private message channels).
ls n/a n/a n/a An alias for list.
message target [message] n/a Send a message to a channel or user. When messaging a user, the message text can be omitted to create a private message channel.
msg target [message] n/a An alias for message.
mode target [mode] [mode parameter] Set various user or channel modes. mode #channel +b requests the channels banlist. mode #channel requests the current mode.
names channel n/a n/a Request the names listing of a channel.
nick nickname n/a n/a Change your nickname.
notice target [message] n/a Send a notice to a channel or user. The same rules as with message apply.
part target [reason] n/a Leave a channel or close a private message channel.
quit [reason] n/a n/a Disconnect from the server and quit jj.
topic channel n/a n/a Request the topic of a channel.
topicset channel [topic] n/a Set the topic of a channel. Omitting the second parameter removes the channel topic.
whois nickname n/a n/a Request the whois information of a user.

Additionally, the raw command can be used to send IRC commands not supported by jjc(1).

Note: Using raw to message or notice a channel or user results in the message not being printed locally (to the log file). It could be used to auth with services to prevent passwords from being written to the logs.

Environment Variables

Settings

Name Description Default
IRC_CLIENT The program spawned as child of jjd(1) which handles all user and IRC messages. jjc
IRC_DIR Where to store the per-host directories. . (current directory)
IRC_HOST The IRC host to connect to. irc.libera.chat
IRC_NICK The Nickname to use. $USER
IRC_PASSWORD The server password. unset
IRC_PORT Connect using this port. 6667
IRC_REALNAME The real name to use. Can be seen in whois. $USER
IRC_USER The user name to use. $USER

Special Information for Hooks

When Hooks are being run, the following additional environment variables are also available to the called program:

Name Description
IRC_ME Our nickname.
IRC_NETWORK The networks official name as supplied by the server. Like "QuakeNet".
IRC_TEXT The text of a message. Or if the event is a kick, part, or quit, it would contain the reason. If applicable, empty otherwise.
IRC_WHERE In which channel the event happened. If applicable, empty otherwise.
IRC_WHO Who triggered this hook, e.g. the nickname of the message author. If applicable, empty otherwise.
IRC_CASEMAPPING The servers casemapping. For rfc1459 for example, its value would be ][\~A-Z }{|^a-z, which can be split on space and then used as arguments for tr(1), to properly casefold a string.
IRC_AWAY 1 when we are marked away, empty otherwise.

Misc

Name Description
JJ_SERVERLOG When not empty, jjp(1) will print status messages using the default color.
JJ_DEBUG When not emtpy, jjc(1) will print debug output.
NO_COLOR Prevent jjp(1) from printing colors.

Log Format

The general log format is:

1579093317 <user123>n! Hello, World!

The "1579093317" is the seconds since epoch. It can be converted to the current timezone and a readable format, which jjc(1) does automatically. The second part is the nickname of the message author with a suffix indicating message types. The "Hello, World!" is the actual body of the message.

jjc(1) uses the following message type indicators:

  • * - This is us, we are the author of this message.
  • ! - Important information in server.log or our nick is mentioned in this message.
  • n - This message is a notice.
  • :<status>: - A channel message send only to users with a certain status in that channel (@%+ etc).
  • c - A CTCP message.
  • a - an ACTION message.

Note: For messages without an author (server messages), a single dash is used as nickname.

Log Rotation

When jjd(1) receives a SIGUSR1, it will send s <timestamp> SIGUSR1 to $IRC_CLIENT. By default, jjc(1) will close all its open log files when receiving that message. That way, any new messages after that will automatically reopen the log files at their original location, completing the log rotation process.

Hooks

Certain events can trigger the execution of external programs. Those programs have to be executable and in PATH and they are run with an altered environment (See: Environment Variables).

The following programs are supported:

Name Trigger
irc_on_query A private message channel is created.
irc_on_connect Succesfully connecting to the server.
irc_on_ctcp Receiving a CTCP message.
irc_on_highlight Own nick is mentioned in a message.
irc_on_invite Being invited to join a channel.
irc_on_join A channel or private message channel is joined.
irc_on_kick We got kicked from a channel.
irc_on_part A channel is parted.

Note: When a private message contains our nick but also caused the creation of a channel, instead of executing both, irc_on_query and irc_on_highlight, only the former is triggered. Unlike irc_on_join, which is always triggered, irc_on_query is not triggered when we caused the channel creation by messaging another user.

Examples

Securing the Connection

Using TLS via s6-networking utilities

s6-tlsclient irc.libera.chat 6697 jjd

Or using SSL via netcat

ncat -vv --ssl --ssl-verify -c 'exec 6<&0 7>&1; PROTO=lol jjd </dev/tty >/dev/tty' irc.libera.chat 6697

Automatic Reconnection

while :; do jjd; sleep 5; done

Watching Logs

tail -fn100 "$IRC_DIR/$IRC_HOST/channels/#channel.log" | jjp

Ignoring Certain Nicks

tail -fn100 "$IRC_DIR/$IRC_HOST/channels/#channel.log" |
	grep -iv '^.\{10\} <nick>' | jjp

Printing Last n User Messages

tac "$IRC_DIR/$IRC_HOST/channels/#channel.log" |
	grep -m10 -v '^.\{10\} <->' |
	tac | jjp

A Simple Input Method

See jji in extra.

A Sample irc_on_connect

#!/bin/sh -e

fifo=$IRC_DIR/$IRC_HOST/in
[ -p "$fifo" ] && [ -w "$fifo" ] ||
	exit 1

if [ "$IRC_HOST" = irc.libera.chat ]; then
	printf 'raw PRIVMSG NickServ :IDENTIFY jilles foo\n' >"$fifo"
	sleep .5
	printf 'join #jj\n' >"$fifo"
fi

Community

Contributions/Scripts

  • panica - Thin tmux wrapper around jj

IRC

Join #jj on irc.libera.chat