(about-tmux)=

# The Tao of tmux

:::{figure} /\_static/tao-tmux-screenshot.png
:scale: 60%
:align: center

ISC-licensed terminal multiplexer.

:::

tmux is geared for developers and admins who interact regularly with CLI
(text-only interfaces)

In the world of computers, there are 2 realms:

1.  The text realm
2.  The graphical realm

tmux resides in the text realm. This is about fixed-width fonts and that
old fashioned black terminal.

tmux is to the console what a desktop is to gui apps. It's a world
inside the text dimension. Inside tmux you can:

- multitask inside the terminal, run multiple applications.
- have multiple command lines (pane) in the same window
- have multiple windows (window) in the workspace (session)
- switch between multiple workspaces, like virtual desktops

## Thinking tmux

### Text-based window manager

| **tmux**    | **"Desktop"-Speak**             | **Plain English**                     |
| ----------- | ------------------------------- | ------------------------------------- |
| Multiplexer | Multi-tasking                   | Multiple applications simultaneously. |
| Session     | Desktop                         | Applications are visible here         |
| Window      | Virtual Desktop or applications | A desktop that stores it own screen   |
| Pane        | Application                     | Performs operations                   |

```{eval-rst}
.. aafig::
    :textual:

    +----------------------------------------------------------------+
    |  +--------+--------+ +-----------------+ +-----------------+   |
    |  | pane   | pane   | | pane            | | pane            |   |
    |  |        |        | |                 | |                 |   |
    |  |        |        | |                 | |                 |   |
    |  +--------+--------+ |                 | +-----------------+   |
    |  | pane   | pane   | |                 | | pane            |   |
    |  |        |        | |                 | |                 |   |
    |  |        |        | |                 | |                 |   |
    |  +--------+--------+ +-----------------+ +-----------------+   |
    |  | window          | | window          | | window          |   |
    |  \--------+--------/ \-----------------/ \-----------------/   |
    +----------------------------------------------------------------+
    | session                                                        |
    \----------------------------------------------------------------/
```

- 1 {term}`Server`.

  - has 1 or more {term}`Session`.

    - has 1 or more {term}`Window`.

      - has 1 or more {term}`Pane`.

:::{seealso}

{ref}`glossary` has a dictionary of tmux words.

:::

### CLI Power Tool

Multiple applications or terminals to run on the same screen by
splitting up 1 terminal into multiple.

One screen can be used to edit a file, and another may be used to
`$ tail -F` a logfile.

```{eval-rst}
.. aafig::

   +--------+--------+
   | $ bash | $ bash |
   |        |        |
   |        |        |
   |        |        |
   |        |        |
   |        |        |
   |        |        |
   +--------+--------+
```

```{eval-rst}
.. aafig::

   +--------+--------+
   | $ bash | $ bash |
   |        |        |
   |        |        |
   +--------+--------+
   | $ vim  | $ bash |
   |        |        |
   |        |        |
   +--------+--------+
```

tmux supports as many terminals as you want.

```{eval-rst}
.. aafig::
   :textual:

   +---------+---------+
   | $ bash  | $ bash  |
   |         |         |
   |         |         |     /-----------------\
   +---------+---------+ --> |'switch-window 2'|
   | $ bash  | $ bash  |     \-----------------/
   |         |         |              |
   |         |         |              |
   +---------+---------+              |
   | '1:sys*  2:vim'   |              |
   +-------------------+              |
             /------------------------/
             |
             v
   +---------+---------+
   | $ vim             |
   |                   |
   |                   |
   +-------------------+
   | $ bash  | $ bash  |
   |         |         |
   |         |         |
   +-------------------+
   | '1:sys  2:vim*'   |
   +-------------------+
```

You can switch between the windows you create.

### Resume everything later

You can leave tmux and all applications running (detach), log out, make
a sandwich, and re-(attach), all applications are still running!

```{eval-rst}
.. aafig::
   :textual:

   +--------+--------+
   | $ bash | $ bash |
   |        |        |
   |        |        |     /------------\
   +--------+--------+ --> |   detach   |
   | $ vim  | $ bash |     | 'Ctrl-b b' |
   |        |        |     \------------/
   |        |        |            |
   +--------+--------+            |
               /------------------/
               |
               v
   +-----------------------+
   | $ [screen detached]   |
   |                       |
   |                       |
   |                       |
   |                       |
   |                       |
   |                       |
   +-----------------------+
              v
              |
              v
   +-----------------------+
   | $ [screen detached]   |
   | $ tmux attach         |
   |                       |     /------------\
   |                       | --> | attaching  |
   |                       |     \------------/
   |                       |            |
   |                       |            |
   +-----------------------+            |
                                        |
            /---------------------------/
            |
            v
   +--------+--------+
   | $ bash | $ bash |
   |        |        |
   |        |        |
   +--------+--------+
   | $ vim  | $ bash |
   |        |        |
   |        |        |
   +--------+--------+
```

### Manage workflow

- System administrators monitor logs and services.
- Programmers like to have an editor open with a CLI nearby.

Applications running on a remote server can be launched inside of a tmux
session, detached, and reattached next time your ["train of
thought"](http://en.wikipedia.org/wiki/Train_of_thought) and work.

Multitasking. Preserving the thinking you have.

## Installing tmux

tmux is packaged on most Linux and BSD systems.

For the freshest results on how to get tmux installed on your system,
"How to install tmux on \<my distro>" will do, as directions change and
are slightly different between distributions.

This documentation is written for version **1.8**. It's important that
you have the latest stable release of tmux. The latest stable version is
viewable on the [tmux homepage](http://tmux.sourceforge.net/).

**Mac OS X** users may install the latest stable version of tmux
through [MacPorts](http://www.macports.org/),
[fink](http://fink.thetis.ig42.org/) or [Homebrew](http://www.brew.sh)
(aka brew).

If **compiling from source**, the dependencies are
[libevent](http://www.monkey.org/~provos/libevent/) and
[ncurses](http://invisible-island.net/ncurses/).

## Using tmux

### Start a new session

```console
$ tmux
```

That's all it takes to launch yourself into a tmux session.

:::{admonition} Common pitfall
:class: note

Running `$ tmux list-sessions` or any other command for listing tmux
entities (such as `$ tmux list-windows` or `$ tmux list-panes`).
This can generate the error "failed to connect to server".

This could be because:

- tmux server has killed its last session, killing the server.
- tmux server has encountered a crash. (tmux is highly stable,
  this will rarely happen)
- tmux has not been launched yet at all.

:::

(prefix-key)=

### The prefix key

Tmux hot keys have to be pressed in a special way. **Read this
carefully**, then try it yourself.

First, you press the _prefix_ key. This is `C-b` by default.

Release. Then pause. For less than a second. Then type what's next.

`C-b o` means: Press `Ctrl` and `b` at the same time. Release, Then
press `o`.

**Remember, prefix + short cut!** `C` is `Ctrl` key.

### Session Name

Sessions can be _named upon creation_.

```console
$ tmux new-session [-s session-name]
```

Sessions can be _renamed after creation_.

```{eval-rst}
=============== =========================================================
Command         .. code-block:: bash

                    $ tmux rename-session <session-name>

Short cut       ``Prefix`` + ``$``
=============== =========================================================
```

### Window Name

Windows can be _named upon creation_.

```console
$ tmux new-window [-n window-name]
```

Windows can be _renamed after creation_.

```{eval-rst}
=============== ==========================================================
Command         .. code-block:: bash

                    $ tmux rename-window <new-name>

Short cut       ``Prefix`` + ``,``
=============== ==========================================================
```

### Creating new windows

```{eval-rst}
=============== =========================================================
Command         .. code-block:: bash

                    $ tmux new-window [-n window-name]

Short cut       ``Prefix`` + ``c``

                You may then rename window.
=============== =========================================================
```

### Traverse windows

By number

```console
$ tmux select-window
```

Next

```console
$ tmux next-window
```

Previous

```console
$ tmux previous-window
```

Last-window

```console
$ tmux last-window
```

| Short cut | Action                                                      |
| --------- | ----------------------------------------------------------- |
| `n`       | Change to the next window.                                  |
| `p`       | Change to the previous window.                              |
| `w`       | Choose the current window interactively.                    |
| `0 to 9`  | Select windows 0 to 9.                                      |
| `M-n`     | Move to the next window with a bell or activity marker.     |
| `M-p`     | Move to the previous window with a bell or activity marker. |

### Move windows

Move window

```console
$ tmux move-window [-t dst-window]
```

Swap the window

```console
$ tmux swap-window [-t dst-window]
```

| Short cut | Action                                          |
| --------- | ----------------------------------------------- |
| `.`       | Prompt for an index to move the current window. |

### Move panes

```console
$ tmux move-pane [-t dst-pane]
```

| Short cut | Action                                           |
| --------- | ------------------------------------------------ |
| `C-o`     | Rotate the panes in the current window forwards. |
| `{`       | Swap the current pane with the previous pane.    |
| `}`       | Swap the current pane with the next pane.        |

### Traverse panes

Shortcut to move between panes.

```console
$ tmux last-window
```

```console
$ tmux next-window
```

| Short cut     | Action                                              |
| ------------- | --------------------------------------------------- |
| `Up, Down`    | Change to the pane above, below, to the left, or to |
| `Left, Right` | the right of the current pane.                      |

Recipe: tmux conf to `hjkl` commands, add this to your `~/.tmux.conf`:

    # hjkl pane traversal
    bind h select-pane -L
    bind j select-pane -D
    bind k select-pane -U
    bind l select-pane -R

### Kill window

```console
$ tmux kill-window [-t target-window]
```

| Short cut | Action                   |
| --------- | ------------------------ |
| `&`       | Kill the current window. |

### Kill pane

```console
$ tmux kill-pane [-t target-pane]
```

| Short cut | Action                 |
| --------- | ---------------------- |
| `x`       | Kill the current pane. |

### Splitting windows into panes

```console
$ tmux split-window [-c start-directory] <shell-command>
```

Tmux windows can be split into multiple panes.

| Short cut | Action                                           |
| --------- | ------------------------------------------------ |
| `%`       | Split the current pane into two, left and right. |
| `"`       | Split the current pane into two, top and bottom. |

## Configuring tmux

Tmux can be configured via a `tmux(1)` configuration at `~/.tmux.conf`.

Depending on your tmux version, there is different options available.

### Vi-style copy and paste

```console
# Vi copypaste mode
set-window-option -g mode-keys vi
bind-key -t vi-copy 'v' begin-selection
bind-key -t vi-copy 'y' copy-selection
```

### Aggressive resizing for clients

```console
setw -g aggressive-resize on
```

### Reload config

`<Prefix>` + `r`.

```console
bind r source-file ~/.tmux.conf \; display-message "Config reloaded."
```

### Status lines

Tmux allows configuring a status line that displays system information,
window list, and even pipe in the `stdout` of an application.

You can use [tmux-mem-cpu-load][tmux-mem-cpu-load] to get stats (requires compilation) and
[basic-cpu-and-memory.tmux][basic-cpu-and-memory.tmux]. You can pipe in a bash command to a tmux
status line like:

```console
$(shell-command)
```

So if `/usr/local/bin/tmux-mem-cpu-load` outputs stats to `stdout`, then
`$(tmux-mem-cpu-load)` is going to output the first line to the status
line. The interval is determined by the `status-interval`:

    set -g status-interval 1

[tmux-mem-cpu-load]: https://github.com/thewtex/tmux-mem-cpu-load
[basic-cpu-and-memory.tmux]: https://github.com/zaiste/tmuxified/blob/master/scripts/basic-cpu-and-memory.tmux

### Examples

- <https://github.com/tony/tmux-config> - works with tmux 1.5+.
  Supports screen's `ctrl-a` `Prefix key`. Support for system cpu,
  memory, uptime stats.
- Add yours, edit this page on github.

## Reference

### Short cuts

:::{tip}

{ref}`prefix-key` is pressed before a short cut!

:::

| Short cut                        | Action                                                                                                                     |
| -------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| `C-b`                            | Send the prefix key (C-b) through to the application.                                                                      |
| `C-o`                            | Rotate the panes in the current window forwards.                                                                           |
| `C-z`                            | Suspend the tmux client.                                                                                                   |
| `!`                              | Break the current pane out of the window.                                                                                  |
| `"`                              | Split the current pane into two, top and bottom.                                                                           |
| `#`                              | List all paste buffers.                                                                                                    |
| `$`                              | Rename the current session.                                                                                                |
| `%`                              | Split the current pane into two, left and right.                                                                           |
| `&`                              | Kill the current window.                                                                                                   |
| `'`                              | Prompt for a window index to select.                                                                                       |
| `,`                              | Rename the current window.                                                                                                 |
| `-`                              | Delete the most recently copied buffer of text.                                                                            |
| `.`                              | Prompt for an index to move the current window.                                                                            |
| `0 to 9`                         | Select windows 0 to 9.                                                                                                     |
| `:`                              | Enter the tmux command prompt.                                                                                             |
| `;`                              | Move to the previously active pane.                                                                                        |
| `=`                              | Choose which buffer to paste interactively from a list.                                                                    |
| `?`                              | List all key bindings.                                                                                                     |
| `D`                              | Choose a client to detach.                                                                                                 |
| `[`                              | Enter copy mode to copy text or view the history.                                                                          |
| `]`                              | Paste the most recently copied buffer of text.                                                                             |
| `c`                              | Create a new window.                                                                                                       |
| `d`                              | Detach the current client.                                                                                                 |
| `f`                              | Prompt to search for text in open windows.                                                                                 |
| `i`                              | Display some information about the current window.                                                                         |
| `l`                              | Move to the previously selected window.                                                                                    |
| `n`                              | Change to the next window.                                                                                                 |
| `o`                              | Select the next pane in the current window.                                                                                |
| `p`                              | Change to the previous window.                                                                                             |
| `q`                              | Briefly display pane indexes.                                                                                              |
| `r`                              | Force redraw of the attached client.                                                                                       |
| `s`                              | Select a new session for the attached client interactively.                                                                |
| `L`                              | Switch the attached client back to the last session.                                                                       |
| `t`                              | Show the time.                                                                                                             |
| `w`                              | Choose the current window interactively.                                                                                   |
| `x`                              | Kill the current pane.                                                                                                     |
| `{`                              | Swap the current pane with the previous pane.                                                                              |
| `}`                              | Swap the current pane with the next pane.                                                                                  |
| `~`                              | Show previous messages from tmux, if any.                                                                                  |
| `Page Up`                        | Enter copy mode and scroll one page up.                                                                                    |
| `Up, Down`                       | Change to the pane above, below, to the left, or to                                                                        |
| `Left, Right`                    | the right of the current pane.                                                                                             |
| `M-1 to M-5`                     | Arrange panes in one of the five preset layouts: even-horizontal, even-vertical, main-horizontal, main-vertical, or tiled. |
| `M-n`                            | Move to the next window with a bell or activity marker.                                                                    |
| `M-o`                            | Rotate the panes in the current window backwards.                                                                          |
| `M-p`                            | Move to the previous window with a bell or activity marker.                                                                |
| `C-Up, C-Down` `C-Left, C-Right` | Resize the current pane in steps of one cell.                                                                              |
| `M-Up, M-Down` `M-Left, M-Right` | Resize the current pane in steps of five cells.                                                                            |

Source: tmux manpage[1].

To get the text documentation of a `.1` manual file:

```console
$ nroff -mdoc tmux.1|less
```

For more information on how to export and differentiate tmux between versions, see https://github.com/tmux-python/tmux-manuals.

[^id2]: <http://sourceforge.net/p/tmux/tmux-code/ci/master/tree/tmux.1>

[creative commons by-nc-nd 3.0 us]: http://creativecommons.org/licenses/by-nc-nd/3.0/us/

### The Book

:::::::{container} book-container

::::{container} leftside-book

:::{figure} https://s3.amazonaws.com/titlepages.leanpub.com/the-tao-of-tmux/large
:scale: 100%
:width: 301
:height: 390
:align: left
:target: https://leanpub.com/the-tao-of-tmux
:alt: The Tao of tmux

:::

::::

::::{container} rightside-book

_The Tao of tmux_ is available on [Leanpub][leanpub] and [Kindle][kindle] (Amazon).

:::{figure} \_static/img/books/amazon-logo.png
:scale: 19%
:target: http://amzn.to/2gPfRhC
:alt: Amazon Kindle

:::

Read and browse the book for [free on the web][free on the web].

::::

[free on the web]: https://leanpub.com/the-tao-of-tmux/read
[leanpub]: https://leanpub.com/the-tao-of-tmux
[kindle]: http://amzn.to/2gPfRhC

:::::::

### License

This page is licensed [Creative Commons BY-NC-ND 3.0 US][creative commons by-nc-nd 3.0 us].
