Save byobu (a tmux wrapper) sessions to a shell script that can be run to restore the session.

byobu-persist.rb

#!/usr/bin/env ruby

# Modified version of https://github.com/geebee/tmux-persistence to work with byobu
# and work on OSX.

require 'fileutils.rb'

# Start - Configuration Variables
sessionDir = ENV['HOME']+"/.byobu-sessions"
maxStoredSessions = 5
filesToRoll = 3
# End - Configuration Variables

FileUtils::makedirs(sessionDir) unless File.exists?(sessionDir)

files = []
Dir.entries(sessionDir).each do |e|
  if e !~ /^\./
    files << e
  end
end
files.sort! unless files.length == 0

if files.length > maxStoredSessions
  0.upto(filesToRoll - 1) do |index|
    File.delete( sessionDir+ "/" + files[index] )
  end
  puts "Rotated stored sessions"
end

#%x[rm #{sessionDir}/*-restore]

sessions = %x[tmux list-sessions -F "\#{session_name}"].split("\n")

sessions.each do |sessionName|
  rawPaneList = %x[tmux list-panes -t #{sessionName} -s -F "\#{window_index} \#{pane_index} \#{window_width} \#{window_height} \#{pane_width} \#{pane_height} \#{window_name} \#{pane_current_path} \#{pane_pid}"].split("\n")

  panes = []
  rawPaneList.each do |pane_line|
    temp_pane = pane_line.split(" ")
    panes.push({
      windowIndex: Integer(temp_pane[0]),
      paneIndex: Integer(temp_pane[1]),
      windowWidth: Integer(temp_pane[2]),
      windowHeight: Integer(temp_pane[3]),
      paneWidth: Integer(temp_pane[4]),
      paneHeight: Integer(temp_pane[5]),
      window_name: temp_pane[6],
      cwd: temp_pane[7],
      pid: temp_pane[8]
    })
  end

  sessionScript = ""
  panes.each_index do |idx|
    pane = panes[idx]
    pane[:cmd] = %x[ps -o command -p #{pane[:pid]} | awk 'NR>1'].delete("\n")
    pane[:cmd] = %x[ps -o command #{pane[:pid]} | awk 'NR>1'].delete("\n").gsub(/^-/,"") unless pane[:cmd] != ""

    sessionScript += "  # Restore (forcibly) window '#{pane[:window_name]}' to position #{pane[:windowIndex]}\n"
    sessionScript += "  $BYOBU new-window -t $SESSION:#{pane[:windowIndex]} -k -n #{pane[:window_name]}\n"
    sessionScript += "  $BYOBU send-keys -t $SESSION:#{pane[:windowIndex]} 'cd \"#{pane[:cwd]}\" && clear' C-m\n\n"

    if pane[:paneIndex] > 0
      if pane[:paneWidth] < pane[:windowWidth]
        sessionScript += "  $BYOBU join-pane -h -l #{pane[:paneWidth]} -s $SESSION:#{pane[:windowIndex] +1}.0 -t $SESSION:#{pane[:windowIndex]}\n\n"
      else
        sessionScript += "  $BYOBU join-pane -v -l #{pane[:paneHeight]} -s $SESSION:#{pane[:windowIndex] +1}.0 -t $SESSION:#{pane[:windowIndex]}\n\n"
      end
    end
  end

  restore_file = sessionDir + "/" + sessionName + "-restore"

  File.open(restore_file, "w") {
    |f| f.write(%Q[#!/usr/bin/env bash
SESSION=#{sessionName}
BYOBU=\\byobu           # bypass any aliasing

if [ -z $TMUX ]; then

  # if session already exists, attach
  $BYOBU has-session -t $SESSION 2>/dev/null
  if [ $? -eq 0 ]; then
    echo \"Session $SESSION already exists. Attaching...\"
    $BYOBU attach -t $SESSION
    exit 0;
  fi

  # assumption by this point is user hasn't already started tmux/byobu, since we lazily quit if there was one
  # (could be done, but this isn't my job...and I need to get to my job).

  # Refactored to work even if user has some default session creation already configured in their ~/.byobu/.tmux.conf

  $BYOBU start-server

#{sessionScript}

  # attach to new session
  $BYOBU select-window -t $SESSION:#{panes[0][:windowIndex]}
  $BYOBU attach-session -t $SESSION

fi
  ])

    # make script executable
    f.chmod( 0744 )
  }
end

This doesn't work.

So I looked at the bash code. I'm not good at bash, I know nothing about ruby but I made it work (hackfix I guess).

I only added this line:
$BYOBU new -s $SESSION

After:
$BYOBU start-server

Although it annoyed me to install ruby-full only for that small script but well, it seems like it works!

EDIT: if you close one window, and you rerun the script, it won't restore that closed window.
EDIT 2: if you kill the byobu server, if you delete all sessions, and if you restore using the script, it won't reload any history, just the names and number of windows :'(
EDIT 3: ok it's too buggy lol, I can't make it work
EDIT 4: maybe guys should try tmux-resurrect instead