1. tmux Nicholas Marriott 2011

2. What is tmux? Terminal multiplexer...
Text program with three main features:
Run multiple programs inside tmux and swap between them interactively
Detach from the terminal and reattach later
Move between terminals without affecting programs inside tmux
Lots of other stuff but those are the biggest

3. Some background tmux started in 2007 Entirely in C, about 30K LOC now
Imported into OpenBSD base system in 2009
Portable version on SF
Runs on *BSD, Linux, Solaris, AIX, HP-UX
Currently version 1.4, probably 1.5 soon
I'm the main developer but there are several other regular/significant contributors

4. So it's like GNU screen then?
Yes, similar ideas
Similar abilities too now but different design
tmux rarely based on how screen does things - I don't use it much

5. But what's different? I haven't used GNU screen for a while but:
tmux is BSD licensed
tmux has a much more modern code style
tmux is actively developed and released
tmux is client-server and uses libevent
Pane management is significantly different
Fewer limits, better for emacs users (like me!)
A lot of other stuff too

6. tmux terminology One server process - socket in /tmp
Server contains sessions which contain windows which can be split into panes which contain running programs
Clients attach to server and display a session
Clients are dumb - server does pretty much everything
Windows have indexes (0, 1, 9999) and names (ksh, mutt, my_name, whatever)

7. What can tmux do? Some of the things I use a lot:
Client-server, session management
Window panes and layouts
Copy and paste
Big, flexible command set
Automatic window renaming

8. Client-server
(Normally) one tmux server controls all terminals, child programs and so on
Good:
Move windows between sessions
Change client session w/o reattach
Global configuration and copy buffers
Bad:
If server dies, all is lost (but rare!)

9. Session management
Attach one client and switch it between sessions w/o attach and detach
Sessions can be like workspaces for different tasks
Move windows between sessions or link them into multiple sessions
Interactive menu to move between sessions
At work I can get to >50 sessions over a few months

10. Window panes
Split a window into arbitrary horizontal and vertical panes
Arguments about which is horizontal and which vertical notwithstanding
Preset window layouts (tiled, horizontal and more)
Can set up and apply user layouts
synchronize-panes option sends input to all panes (very useful with many servers!)

11. Copy and paste
Copy mode can copy text from visible pane or scrolled history
vi and emacs key bindings!
Copy mode very usable - search, mouse support, try to match editors
Global stack of paste buffers (in 1.5) across sessions
Save and load buffers to file, stdout

12. Command set tmux has about 80 commands now
Commands have long forms and aliases
Almost all can be used the same inside tmux, config or shell
Great for scripting:
for i in `jot 10`; do
tmux splitw "ssh host$i"; tmux selectl tiled
done

13. Command set (more) Command sequences (lsk; lsk; lsk)
Command prompt: enter command interactively
Or prompt and substitute:
bind ',' command-prompt "rename-window '%%'"
confirm-before command prompts for y/n:
bind 'x' confirm-before kill-pane

14. Command targets Almost all commands accept a target argument
Unified way to address clients, windows, panes
tmux will make best guess for pretty much anything omitted
Example to swap pane 0 in window 1 in session A with pane 2 in the current window:
tmux swap-pane -s A:1.0 -t :.2

15. Automatic rename Only platform-specific code in tmux proper
Automatically figure out what is running in window and rename it
Uses sysctl on *BSD, /proc on Linux
Not as hacky as scraping stuff from the shell prompt and easier to configure (on by default)
But doesn't follow over ssh
Also can be a little slow on older boxes (best to turn off on your vax)

16. What else is sort of cool?
pipe-pane command - send all output to a pipe
Mouse support - improved a lot for 1.5 thanks to a contributor, drag pane borders to resize etc
Search for window containing text
Very customisable, status line, messages log
256 colour and UTF-8 support
Bell/activity monitoring
Visual pane identification (shows numbers)
ASCII art clock!

17. What can't tmux do? Big problems right now:
Panes can only be in one window - simpler to get panes working at first, hard to change now
Windows cannot be bigger than smallest client (no panning)
UTF-8 support needs improvement
Huge todo list!

18. What's coming up? Diff CVS to tmux 1.4 is already 18000 lines
I have mails in my inbox now for more mouse improvements and handling of cursor colour/style changes
Author of iterm has been investigating integrating it and tmux (really cool)
I'm working on more flexible ways to format list output (such as custom ways to list sessions)
Suggestions welcome

19. How does it work? Pseudoterminals (ptys)
Applications inside output to pty slave in TERM=screen format
tmux reads from pty master and updates internal representation of terminal
Also translates into client TERM and outputs
Lots of other jazz to handle key bindings, commands, mouse and so on

20. Where can I get it? SourceForge http://tmux.sf.net
Highly recommended to use CVS and report bugs - early testing means better releases
OpenBSD base system
Packages or ports for most other platforms
For help:
tmux-users mailing list
IRC channel #tmux on Freenode

21. Questions?