Hey tmux!
Tmux scripting made easy.
Installation
Heytmux requires Ruby 2.0+ and tmux 2.3+.
As Ruby gem
gem install heytmux
- Installs
heytmux
executable
As Vim plugin
Using vim-plug:
Plug 'junegunn/heytmux'
- Registers
:Heytmux
command - No need to install Gem if you only use Heytmux inside Vim
- But if you want it to be globally available,
Plug 'junegunn/heytmux', { 'do': 'gem install heytmux' }
- But if you want it to be globally available,
Usage
Create a YAML file that describes a desired tmux workspace.
# workspace.yml
- first window:
layout: tiled
panes:
- first pane: sleep 1
- second pane: sleep 2
- third pane: |
sleep 3
sleep 4
- second window:
layout: even-vertical
pane-border-status: top
synchronize-panes: true
panes:
- pane 2-1: sleep 5
- pane 2-2: sleep 6
Then run heytmux workspace.yml
.
Instead of creating a new session from scratch, Heytmux looks at the current session and only creates windows and panes that are not found. So you can repeatedly run the same input file only to issue commands on the existing panes.
Heytmux identifies windows and panes by their names and titles, so renaming them can confuse Heytmux. Duplicate names are okay as long as you don't reorder windows or panes of the same names.
More examples can be found here.
Heytmux can read STDIN, so cat workspace.yml | heytmux
is also
valid. It may seem pointless, but it allows you to do :w !heytmux
with a visual selection in Vim.
Step-by-step tutorial
List of window names
In the simplest case, input file only has to contain the names of windows as
the top-level list. Create workspace.yml
and add the following lines.
- window 1
- window 2
- window 3
heytmux workspace.yml
will create 3 windows with the given names. If you
re-run the same command, you'll notice Heytmux doesn't create more windows as
they already exist.
Windows and panes
Well, that was not particularly interesting. Let's split the windows and run some commands.
First run heytmux --kill workspace.yml
to kill the windows we just created,
and update your input file as follows:
- window 1:
- echo 1-1
- echo 1-2
- echo 1-3
- window 2:
- echo 2-1
- echo 2-2
- window 3:
- sleep 3
Run Heytmux with it and you'll see that panes are created under the windows to run those commands. If you rerun the same command, Heytmux will send them again to the same panes. No new panes are created.
Pane titles
However, if you change a command on the input file (e.g. echo 1-1
to
sleep 1
) and run Heytmux, a new pane for the command will be created. That's
because Heytmux identifies windows and panes by their names and titles, and in
the above case, the title of a pane is implicitly set to the given command. So
changing the command changes the identifier of the pane, and Heytmux no longer
can find the previous pane.
To reuse the existing panes, you have to explictly name the panes. Update the
input file, close the windows (heytmux --kill workspace.yml
), and rerun the
command.
- window 1:
- pane 1: sleep 1
- pane 2: sleep 2
- pane 3: sleep 3
- window 2:
- pane 2-1: sleep 1
- pane 2-2: |
sleep 2
sleep 3
Now, you can freely change the commands without worrying about getting extra panes. You can also create and use input files for any subset of the panes.
# In another file
- window 2:
- pane 2: echo 'I slept 5 seconds!'
Window layout and options
What if we want to change the layout of the windows, or if we want to set some
window options of tmux? To do that, move the list of panes to panes
under
each window entry, so you can specify additional settings.
- window 1:
layout: even-horizontal
synchronize-panes: true
pane-border-status: bottom
panes:
- pane 1: sleep 1
- pane 2: sleep 2
- pane 3: sleep 3
- window 2:
layout: even-horizontal
synchronize-panes: true
pane-border-status: top
panes:
- pane 2-1: sleep 1
- pane 2-2: |
sleep 1
sleep 2
Root layout and options
That's nice, but looks like we're repeating ourselves with the same options. We can reorganize the input file as follows to define the root layout and options that are applied to all windows.
layout: even-horizontal
synchronize-panes: true
pane-border-status: bottom
windows:
- window 1:
panes:
- pane 1: sleep 1
- pane 2: sleep 2
- pane 3: sleep 3
- window 2:
# Override root option
pane-border-status: top
panes:
- pane 2-1: sleep 1
- pane 2-2: |
sleep 1
sleep 2
{{ item }}
Expanding panes with The panes under window 1
in the previous example are similar in their names
and commands, and this is a very common case. To avoid repetition, set items
list for a window, then panes with {{ item }}
in their titles will be
expanded according to the list.
# Equivalent to the previous example
- window 1:
items: [1, 2, 3]
panes:
- pane {{item}}: sleep {{item}}
Note that you have to quote a pane title if it starts with {{
.
This is often useful when you have to work with a series of log files or with a set of servers.
- servers:
layout: tiled
items:
- west-host1
- west-host2
- east-host1
- east-host2
panes:
- ssh user@{{item}} tail -f /var/log/server-{{item}}.log
Also note that {{ item.index }}
expands to zero-based index of the item.
Referring to environment variables
You can refer to environment variables using {{ $ENV_VAR }}
syntax. For
default values, use {{ $ENV_VAR | the-default-value }}
syntax. Heytmux will
not start if an environment variable is not defined and there's no default
value.
Expecting pattern
Sometimes it's not enough to just send lines of text at once. For example, the following example will not work as expected.
- servers:
- server 1: |
ssh server1
{{ $MY_SSH_PASSWORD }}
uptime
With expect
construct, you can make Heytmux wait until a certain regular
expression pattern appears on the pane (a la Expect).
- servers:
- server 1:
- ssh server1
- expect: '[Pp]assword:'
- {{ $MY_SSH_PASSWORD }}
- uptime
Special commands
In addition to expect
, Heytmux also supports sleep
and keys
commands.
sleep
suspends the execution for a given time period. It's useful when the
shell on the target pane is non-interactive so you can't send sleep
command
to it. keys
command is for sending special keys, such as c-c
(CTRL-C)
using tmux send-keys
command. To send multiple keys, specify the keys as
a YAML list (e.g. [c-c, c-l]
).
- servers:
- server 1:
- vmstat 2 | tee log
- sleep: 3
- keys: c-c
Vim plugin
You don't really need a Vim plugin for Heytmux (because :w !heytmux
will
just do), but here's one anyway, to save you some typing.
:Heytmux [OPTIONS]
- Run with the current file
:Heytmux [OPTIONS] FILES...
- Run with the files
:'<,'>Heytmux [OPTIONS]
(in visual mode)- Run with the given range
Use bang version of the command (:Heytmux!
) not to move focus. It is
equivalent to passing -d
flag to heytmux executable.
Related projects
Many of the ideas were borrowed from Tmuxinator and Ansible, but Heytmux solves a different problem.
There are also other projects that are similar to tmuxinator.
How is this different from tmuxinator?
With Tmuxinator, you can manage session configurations each of which defines the initial layout of a tmux session.
On the other hand, Heytmux does not care about sessions, instead it simply creates windows and panes on the current session, and it only creates the ones that don't exist. So it can be used not only to bootstrap the initial workspace, but also to send commands to any subset of the existing panes, which means you can use it for scripting your tasks that span multiple tmux windows and panes. Heytmux somehow feels like a hybrid of Tmuxinator and Ansible.
I primarily use Heytmux to write Markdown documents with fenced code blocks of YAML snippets that I can easily select and run with Heytmux in my editor.
License
MIT