Commands

$ tmux
  -u # UTF8 mode
  -S ~/.tmux.socket

Sessions

$ tmux new
$ tmux new -s session_name

$ tmux attach # Default session
$ tmux attach -s session_name

$ tmux switch -t session_name

$ tmux ls # List sessions

$ tmux detach

Windows

$ tmux new-window

Help

C-b ?

Scrolling

C-b [ # Enter scroll mode then press up and down

Copy/paste

C-b [ # 1. Enter scroll mode first.
Space # 2. Start selecting and move around.
Enter # 3. Press enter to copy.
C-b ] # Paste

Panes

C-b v # vert
C-b n # horiz
C-b hkjl # navigation
C-b HJKL # resize
C-b o # next window
C-b x # close pane

C-b { or } # move windows around

Windows

C-b c # New window
C-b 1 # Go to window 1

Detach/attach

C-b d # Detach
C-b ( ) # Switch through sessions
$ tmux attach

Niceties

C-b t # Time

Status formats

setw -g window-status-format `#[fg=8,bg=default]#I`

See message-command-style in the man page.
Attribute/colors
#[fg=1] standard color
#[fg=yellow] yellow
#[bold] bold
#[fg=colour240] 256 color
#[fg=default] default
#[fg=1,bg=2] combinations
#[default] reset
Colors

    black red green yellow blue magenta cyan white
    brightred (and so on)
    colour0 … colour255
    #333 (rgb hex)

Attributes

    bold underscore blink noreverse hidden dim italics

Variables
#(date) shell command
#I window index
#S session name
#W window name
#F window flags
#H Hostname
#h Hostname, short
#D pane id
#P pane index
#T pane title
Options

set -g status-justify [left|centre|right]
set -g status-left '...'

setw -g window-status-style
setw -g window-status-activity-style
setw -g window-status-bell-style
setw -g window-status-content-style
setw -g window-status-current-style
setw -g window-status-last-style

setw -g window-status-format
setw -g window-status-current-format

setw -g window-status-separator

…Get back