Você não faz isso.
Consulte a seção "FILE DE INICIALIZAÇÃO" do manual de readline ( man readline ):
Readline is customized by putting commands in an initialization file (the inputrc file). The name of this file is taken from the value of the INPUTRC environment variable. If that variable is unset, the default is ~/.inputrc. If that file does not exist or cannot be read, the ultimate default is /etc/inputrc. When a program which uses the readline library starts up, the init file is read, and the key bindings and variables are set.