irssi/docs/help/in/eval.in

%9Syntax:%9

@SYNTAX:eval@

%9Parameters:%9

    The commands to evaluate.

%9Description:%9

    Evaluates the given commands and executes them; you can use internal
    variables and separate multiple commands by using the ';' character.
    If the command contains a string with '$', '\' or ';' those characters 
    need to be escaped:
        '$' -> '$$'
        '\' -> '\\' (or even '\\\\', depending on where they are used)
        ';' -> '\;'

%9Examples:%9

    /EVAL echo I am connected to ${S} on ${chatnet} as ${N}
    /EVAL echo My user privileges are +${usermode}; echo Let's party!
    to print '1;2$3\4': /EVAL echo 1\;2$$3\\4       

%9References:%9

    https://github.com/irssi/irssi/blob/master/docs/special_vars.txt

%9See also:%9 CAT, CD, ECHO, EXEC