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How to enable logging in tmux?

Quick Answer

To log tmux pane output to a file, use the pipe-pane command with a shell command that redirects to a file. Press Ctrl+b : then type pipe-pane -o "cat >> ~/tmux-log.txt". This logs all output from the current pane to the file. Use pipe-pane without arguments to stop logging. For more control, use the tmux-logging plugin, which adds key bindings for logging, screen capture, and save complete history functionality. 

# Start logging current pane
Ctrl+b :pipe-pane -o "cat >> ~/tmux-log.txt"

# Stop logging
Ctrl+b :pipe-pane

# Log with timestamp in filename
Ctrl+b :pipe-pane -o "cat >> ~/tmux-$(date +%Y%m%d-%H%M%S).log"

Detailed Explanation

tmux provides several ways to log the output of panes, which is useful for recording terminal sessions, capturing command outputs, and maintaining history of your work.

Built-in Logging with pipe-pane

The pipe-pane command is tmux's built-in mechanism for logging pane output. It pipes all output that would appear in the pane to a shell command: 

# Basic logging to a file
tmux pipe-pane -o "cat >> ~/tmux-log.txt"

# Log with timestamp in filename
tmux pipe-pane -o "cat >> ~/tmux-$(date +%Y%m%d-%H%M%S).log"

# Only log stdout (no stderr)
tmux pipe-pane -o "cat > ~/tmux-stdout.log"

# Only log stderr (no stdout)
tmux pipe-pane -o "cat > /dev/null 2>> ~/tmux-stderr.log"

Options for the pipe-pane command:

  • -o - Only pipes new output, not existing content
  • -I - Also pipes input to the pane
  • Without arguments, pipe-pane stops any active logging

To log a different pane than the current one, specify the target: 

# Log a specific pane by index
tmux pipe-pane -t 0:1.2 -o "cat >> ~/pane-1-2.log"

# Log a specific session:window.pane
tmux pipe-pane -t mysession:2.1 -o "cat >> ~/specific-pane.log"

Using the tmux-logging Plugin

For more advanced logging features, the tmux-logging plugin offers a comprehensive solution: 

# Install with TPM (Tmux Plugin Manager)
# Add to ~/.tmux.conf
set -g @plugin 'tmux-plugins/tmux-logging'

# If using TPM, press Ctrl+b I to install

The tmux-logging plugin provides several useful key bindings:

  • Ctrl+b Shift+p - Toggle logging on/off (saves to ~/tmux-logging)
  • Ctrl+b Alt+p - Save visible text in the pane
  • Ctrl+b Alt+Shift+p - Save complete pane history
  • Ctrl+b Alt+c - Clear pane history

Logging with External Tools

For even more control, you can use pipe-pane with external tools: 

# Log with timestamps before each line using 'ts' (moreutils package)
tmux pipe-pane -o "cat | ts '%Y-%m-%d %H:%M:%S' >> ~/tmux-timestamped.log"

# Log with rotated log files using 'rotatelogs' (apache2-utils package)
tmux pipe-pane -o "cat | rotatelogs -n 5 ~/tmux-log.%i.txt 10M"

# Log with compression
tmux pipe-pane -o "cat | gzip > ~/tmux-log.gz"
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