Setting up IRSSI

Choose your IRC network servers.

Install Irssi e.g. on Ubuntu,

sudo apt install irssi

Eventually launch/quit Irssi just to backup the default config,

irssi
/quit
cp -pi ~/.irssi/config ~/.irssi/config.dist

Choose a theme of your preference: http://irssi-import.github.io/themes/

cd ~/.irssi/
wget http://irssi-import.github.io/themes/simplicity.theme
wget http://irssi-import.github.io/themes/simpleii.theme
wget http://irssi-import.github.io/themes/simple.theme
wget http://irssi-import.github.io/themes/agon.theme

Choose your IRCnet server: http://www.irchelp.org/networks/servers/ircnet.html / http://irc.tu-ilmenau.de/all_servers/

And your Freenode SSL port: https://freenode.net/kb/answer/chat

Now launch Irssi and setup a few networks, e.g.,

screen -S chat
irssi

#/set nick NICKNAME
/set real_name REALNAME
/set alternate_nick ALTERNATE_NICKNAME

/set theme agon
/set beep_msg_level
/set beep_msg_level MSGS HILIGHT DCCMSGS NOTICES DCC CTCP

/set autolog on
/set completion_char ,
/set completion_nicks_lowercase on

Connect to servers,

/server add -auto -network IRCnet
#/server add -auto -network IRCnet ircnet.nerim.fr

/server add -auto -network Freenode
#/server add -auto -network Freenode chat.freenode.net
/network add -autosendcmd "/msg nickserv identify PASSWORD_HERE; wait 2000" Freenode

/server add -network Onlinenet irc.online.net
/network add Online

Join channels,

/channel add -auto #CHANNEL IRCnet
/channel add -auto #CHANNEL Freenode
/channel add -auto #online Online

Save,

/save

Refs.