My .tmux.conf file with ` as the meta key

.tmux.conf

# remap prefix to Control + a
# set -g prefix C-a
# unbind C-b
# bind C-a send-prefix

unbind C-b
set -g prefix `
bind-key ` send-prefix

set-option -g "screen-256color"

# meta key k will clear screen
bind -n C-k clear-history
bind -n C-k send-keys -R \; clear-history
# force a reload of the config file
unbind r
bind r source-file ~/.tmux.conf

# quick pane cycling
unbind ^A
bind ^A select-pane -t :.+

set-window-option -g allow-rename off
#/Users/sjohnson/.tmux.conf:23: usage: set-option [-agosquw] [-t target-session|target-window] option [value]
set-option -g history-limit 10000

setw -g mode-bg red
set-option -g default-terminal "screen-256color" #"xterm-256color" # "screen-256color"
set-option -g pane-active-border-fg green