tmux

tmux keeps terminal sessions running in the background and splits one terminal into panes. If your SSH connection drops, the session keeps running — reattach with tmux attach.

The installer copies the config but doesn’t install tmux. Install it with your package manager (sudo apt install tmux, brew install tmux).

Files

~/.tmux.conf                    one line: loads ~/.config/tmux/tmux.conf
~/.config/tmux/
├── tmux.conf                   the main config
├── reset.tmux                  clears theme settings before a theme loads
├── catppuccin.tmux             Catppuccin theme (the default)
├── lasik.tmux                  Lasik theme
└── plugins/                    TPM + plugins (cloned by the installer)

~/.tmux.conf is kept so older tmux versions (before 3.1), which don’t look in ~/.config/tmux/, still find the config.

Settings

The prefix is tmux’s “listen to me” key — press it, release, then press the command key. It’s Ctrl+B (the default).

Setting	Effect
Mouse on	click to select panes, drag borders to resize, scroll
Windows and panes start at 1	`1` is easier to reach than `0`
`renumber-windows`	closing window 2 of 3 renames 3 → 2, no gaps
Pane titles on top	each pane shows `1: title` — set with `tmux select-pane -T "logs"`
`extended-keys on`	lets apps tell Shift+Enter from Enter (needed by some coding agents)
24-bit colour	`xterm-256color` plus RGB for kitty

Keys	Action
Prefix “	split top/bottom, in the current folder
Prefix %	split side by side, in the current folder
Prefix c	new window, in the current folder
Prefix r	reload the config and install any new plugins
Prefix I	install plugins (TPM’s key)

By default tmux opens new panes in your home folder; these bindings use the pane’s current folder.

Plugins (TPM)

TPM (Tmux Plugin Manager) downloads and loads plugins listed in tmux.conf. The installer clones TPM into ~/.config/tmux/plugins/tpm (if git is installed).

Plugin	Shows
`tmux-plugins/tmux-cpu`	CPU and RAM use in the status bar
`xamut/tmux-weather`	temperature and an icon for Jyväskylä — change `@tmux-weather-location`

After the first install, open tmux and press Prefix I (capital I, so Shift+i) to download the plugins.

Themes

Catppuccin (Mocha flavour, rounded window tabs) is loaded by default. Its status bar shows the session name on the left, and CPU, RAM, weather, host and date/time on the right. The installer clones Catppuccin’s tmux plugin, version 2.3.0, to ~/.config/tmux/plugins/catppuccin/tmux.

Lasik matches the author’s VSCode theme. Its colours are defined once at the top of lasik.tmux as %hidden variables (tmux’s own variables, not shell ones) — edit those, not the individual set -g lines.

Switch themes in a running tmux:

tmux source-file ~/.config/tmux/lasik.tmux
tmux source-file ~/.config/tmux/catppuccin.tmux

To make Lasik the default, change the source-file line in tmux.conf.

reset.tmux runs first in every theme. tmux remembers style settings while it runs, so without the reset, switching themes leaves old colours showing through.

Edge cases

No git during install → TPM and Catppuccin aren’t cloned; you get the git clone commands to run later. Without Catppuccin, tmux shows an error on start until it’s cloned.
~/.config/tmux is a file, not a folder → the installer stops with an error for tmux.
The weather plugin calls an online service; offline it shows nothing.
tmux-256color would be more accurate than xterm-256color, but it’s missing on older macOS.
Kill the current session: kkk. Start one per project: t.