Tmux

How to use tmux formats for customization?

Quick Answer

Tmux formats use #{variable_name} syntax to insert dynamic information. Use #{session_name} for session name, #{window_name} for window name, and #{pane_current_path} for current directory in status bars and commands.

set-option -g status-right '#{session_name} #{window_index}'

Detailed Explanation

Tmux formats are a powerful templating system that allows you to insert dynamic information into status bars, window titles, and command outputs. They use #{} syntax to reference session, window, and pane properties.

Most Useful Format Variables

# Session info
#{session_name}         # Session name
#{session_windows}      # Number of windows

# Window info
#{window_index}         # Window number (0, 1, 2...)
#{window_name}          # Window name
#{window_panes}         # Number of panes

# Pane info
#{pane_current_path}    # Current directory
#{pane_current_command} # Running command
#{pane_index}           # Pane number

Status Bar Examples

# Basic session and time display
set-option -g status-left '#{session_name}: '
set-option -g status-right '%H:%M %d-%b'

# Show current directory
set-option -g status-right '#{b:pane_current_path} | %H:%M'

# Window list with pane count
set-option -g window-status-format '#{window_index}:#{window_name}'
set-option -g window-status-current-format '[#{window_index}:#{window_name}]'

Conditional Formatting

Use #{?condition,true_value,false_value} for conditional display:

# Show asterisk for active window
#{window_index}:#{window_name}#{?window_active,*,}

# Conditional colors
#{?window_active,#[fg=red],#[fg=white]}#{window_name}#[default]

# Show pane count only if more than 1
#{window_name}#{?#{>:#{window_panes},1}, [#{window_panes}],}

String Operations

# Truncate to 15 characters
#{=15:pane_current_path}

# Get basename of path
#{b:pane_current_path}

# Get directory name
#{d:pane_current_path}

# Search and replace
#{s/home/~/:pane_current_path}

Using Formats in Commands

# Display current info
tmux display-message '#{session_name}: #{window_index}/#{session_windows}'

# List windows with custom format
tmux list-windows -F '#{window_index}: #{window_name} (#{window_panes} panes)'

# Use in key bindings
bind-key i display-message 'Window: #{window_name}, Pane: #{pane_index}'

Pro Tip

Use #{b:pane_current_path} instead of #{pane_current_path} in your status bar to show just the directory name instead of the full path.

Complete Status Bar Example

# Comprehensive status bar in ~/.tmux.conf
set-option -g status-left '#[fg=green]#{session_name}#[default] '
set-option -g status-right '#[fg=blue]#{b:pane_current_path}#[default] | #[fg=yellow]%H:%M#[default]'
set-option -g window-status-format '#{window_index}:#{=10:window_name}'
set-option -g window-status-current-format '#[fg=red,bold]#{window_index}:#{=10:window_name}#[default]'

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