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Overview

tmux has numerous options that control its behavior and appearance. Options can be set at different scopes: server (global), session, window, or pane.

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Option Scopes

  • Server (global) options: Apply to the entire tmux server
  • Session options: Apply to a specific session
  • Window options: Apply to a specific window
  • Pane options: Apply to a specific pane

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set-option

Alias: set 
set-option [-aFgopqsuUw] [-t target-pane] option [value]
Set a window option, session option, or server option.
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-a
flag
Append to a string option. For array options, append to the list.
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-F
flag
Expand formats in the option value.
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-g
flag
Set a global session or window option. This sets the default for all sessions or windows.
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-o
flag
Prevent setting an option that is already set.
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-p
flag
Set a pane option. Pane options are inherited from the window options.
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-q
flag
Suppress errors about unknown or ambiguous options.
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-s
flag
Set a server option.
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-u
flag
Unset an option. For inherited options (window or pane), inherit the value from the parent scope.
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-U
flag
Unset an option without inheriting (removes the option completely).
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-w
flag
Set a window option. This is the default for set-option (can be omitted).
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-t
string
For session options: target session For window options: target window For pane options: target pane
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option
string
required
The option name.
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value
string
The value to set. If omitted, the option is unset.

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Examples

# Set global status bar color
set-option -g status-style bg=blue

# Set option for specific session
set-option -t mysession status-position top

# Append to an option
set-option -ga status-left " [#S]"

# Set window option
set-option -w automatic-rename on

# Set pane option
set-option -p -t 0 remain-on-exit on

# Unset option (inherit from parent)
set-option -u -t mywindow mode-keys

# Set with format expansion
set-option -F message-command-style "fg=#{@my-color}"

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show-options

Alias: show 
show-options [-AgHpqsvw] [-t target-pane] [option]
Show options.
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-A
flag
Include options inherited from a parent scope.
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-g
flag
Show global session or window options.
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-H
flag
Include hooks (omitted by default).
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-p
flag
Show pane options.
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-q
flag
Suppress errors about unknown or ambiguous options.
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-s
flag
Show server options.
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-v
flag
Show only the option value, not the name.
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-w
flag
Show window options. This is the default.
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-t
string
Target pane, window, or session.
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option
string
The option to show. If omitted, all options are shown.

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Examples

# Show all window options
show-options

# Show global session options
show-options -g

# Show specific option value
show-options -gv status-position

# Show server options
show-options -s

# Show pane options
show-options -p -t 0

# Show option including inherited values
show-options -A mode-keys

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set-environment

Alias: setenv 
set-environment [-Fgru] [-t target-session] name [value]
Set or unset an environment variable.
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-F
flag
Expand formats in the value.
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-g
flag
Set in the global environment. This is the default if no target session is specified.
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-r
flag
Mark the variable as removed. It will be removed from the environment when the session is created.
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-u
flag
Unset the variable.
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-t
string
Set the variable in the session environment for the target session.
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name
string
required
The environment variable name.
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value
string
The value to set. Required unless -u is specified.

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Examples

# Set global environment variable
set-environment MYVAR myvalue

# Set for specific session
set-environment -t mysession DISPLAY :0

# Unset variable
set-environment -u MYVAR

# Set with format expansion
set-environment -F CURRENT_WINDOW "#{window_name}"

# Mark as removed
set-environment -r OLDVAR

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show-environment

Alias: showenv 
show-environment [-gs] [-t target-session] [name]
Show environment variables.
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-g
flag
Show the global environment. This is the default if no target session is specified.
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-s
flag
Output in a format suitable for sourcing in a shell.
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-t
string
Show the session environment for the target session.
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name
string
The environment variable to show. If omitted, all variables are shown.

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Examples

# Show all global environment variables
show-environment

# Show session environment
show-environment -t mysession

# Show specific variable
show-environment DISPLAY

# Output in shell-sourceable format
show-environment -s

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Common Options

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Server Options

Set with set-option -s, shown with show-options -s:
  • buffer-limit: Maximum number of automatic paste buffers (default 50)
  • command-alias: List of command aliases
  • default-terminal: Default terminal type (default “screen”)
  • escape-time: Time in milliseconds tmux waits after escape key (default 500)
  • exit-empty: Exit when there are no active sessions (default on)
  • exit-unattached: Exit when no clients are attached (default off)
  • history-file: Path to command history file

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Session Options

Set with set-option, shown with show-options:
  • base-index: Start window numbering at this value (default 0)
  • default-command: Default command for new windows
  • default-shell: Default shell (default $SHELL or /bin/sh)
  • default-size: Default size of windows (default 80x24)
  • display-time: Duration of display-message in milliseconds (default 750)
  • history-limit: Maximum lines per window history (default 2000)
  • key-table: Default key table (default “root”)
  • lock-after-time: Lock session after seconds of inactivity (default 0, disabled)
  • message-style: Style for command prompt messages
  • prefix: Prefix key (default C-b)
  • renumber-windows: Renumber windows when one is closed (default off)
  • repeat-time: Time for repeating key bindings in milliseconds (default 500)
  • status: Show or hide status bar (default on)
  • status-interval: Update status bar every interval seconds (default 15)
  • status-position: Status bar position: top or bottom (default bottom)
  • status-style: Style for status bar

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Window Options

Set with set-option -w, shown with show-options -w:
  • aggressive-resize: Resize window to smallest or largest client (default on)
  • automatic-rename: Automatically rename windows (default on)
  • automatic-rename-format: Format for automatic window names
  • clock-mode-colour: Color of clock
  • clock-mode-style: Clock format: 12 or 24 (default 24)
  • mode-keys: Key bindings in copy mode: vi or emacs (default emacs)
  • mode-style: Style for indicators and highlighting in modes
  • monitor-activity: Monitor for activity in windows (default off)
  • monitor-bell: Monitor for bell in windows (default on)
  • monitor-silence: Monitor for silence (seconds) in windows (default 0, disabled)
  • pane-base-index: Start pane numbering at this value (default 0)
  • remain-on-exit: Keep window after program exits (default off)
  • synchronize-panes: Send input to all panes in the window (default off)
  • window-status-format: Format for window status in status bar
  • window-status-current-format: Format for current window status
  • window-status-style: Style for window status

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Pane Options

Set with set-option -p, shown with show-options -p:
  • allow-passthrough: Allow passthrough sequences (default off)
  • allow-rename: Allow applications to rename windows (default on)
  • alternate-screen: Use alternate screen feature (default on)
  • remain-on-exit: Keep pane after program exits (default off)
  • window-active-style: Style for active pane
  • window-style: Style for inactive panes

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Option Value Types

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Boolean

Values: on, off, yes, no, 1, 0, true, false

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Number

Integer values

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String

Text values, may include format variables

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Style

Style specifications: fg=color, bg=color, bold, dim, underscore, blink, reverse, italics, strikethrough, etc.

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Array

Comma-separated list of values. Use -a to append.

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Color

Color names: black, red, green, yellow, blue, magenta, cyan, white, default Or: colour0 to colour255, #rrggbb hex values