Save log to a file
To save the messages in irssi buffer (for the current channel), just execute the command::
/lastlog -file <filename>
Undefined subroutine &Irssi::statusbar_item_register called at
If you get this error when developing or using a script, the developer probably forgot to use the right module. Add at the top of the file::
I wrote a script that stopped to work after I upgraded Irssi, so I think it is a change added in a newer version of Irssi.