scat

scat is a small app for your terminal. It logs in to your servers with plain SSH and shows you what they are doing. Nothing gets installed on the servers. No agents, no web panel, no passwords stored.

Why you might like it

• 👀 One screen for all servers, grouped the way you like.
• 📊 Detail view with CPU, memory, disks, network and the busiest processes.
• 🔑 Keys only. scat never asks for or stores a password.
• 🐚 Just Bash. No Python, no Node, no extra tools on your servers.
• 🎨 Five colour themes, including a high-contrast one.
• 🐳 Docker, read only: see your containers, nothing gets changed.
• 🌡️ Temperatures and disk health, if you want them. This needs one sudo rule (see below).

Quick start

Takes about five minutes.

1. Get Bash 5

scat needs Bash 5 on the machine you work on (not on your servers). Check your version with bash --version.

Your system	What to do
macOS	brew install bash, then put /opt/homebrew/bin first in your PATH
Linux	Usually there already. Otherwise apt install bash (or dnf / pacman)

The macOS system Bash (version 3.2) is too old and is not supported.

2. Install scat

curl -fsSL https://raw.githubusercontent.com/d3m0naz/scat/main/install.sh | bash
scat --help

The installer downloads the current release and checks its SHA-256 checksum. If the checksum does not match, nothing gets installed.

3. Add your first server

Start scat and press a to add a server. Or write it into the config file yourself, ~/.config/scat/servers.conf:

[web1]
host = 203.0.113.10
user = deploy
group = production

host is the only required line. Anything ssh web1 understands works here, including aliases from ~/.ssh/config.

4. Look, then go

Select a server and press Enter for its details. Press s to open a normal SSH shell on it. q goes back.

Keys to know

Key	What it does
↑ ↓ or j k	move
Enter	open
Esc or q	back
a e d	add, edit, delete a server
s	open an SSH shell on the server
r	refresh now
p	all processes
m	Docker view (if the server has Docker)
t / f	group headings on/off, °C/°F (for this session)
?	help, with every key

The full list is in the reference.

Drive temperatures and health: the sudo rule

scat can show the temperature and health of your disks (SMART). Reading that data needs root rights. scat never asks for a password, so you give it exactly one permission on each server: running smartctl without a password.

On the server (Linux, as an admin user):

1. Create the rule. Replace <scat-user> with the user that scat logs in as:

   <scat-user> ALL=(root) NOPASSWD: /usr/sbin/smartctl -n standby -A /dev/sd[a-z], \
       /usr/sbin/smartctl -n standby -A /dev/sd[a-z][a-z], \
       /usr/sbin/smartctl -n standby -A /dev/nvme[0-9]n[0-9]
   

   Save it with sudo visudo -f /etc/sudoers.d/scat. Use the path that command -v smartctl shows on your system.

2. Check it:

   sudo visudo -cf /etc/sudoers.d/scat   # should say: parsed OK
   sudo -l -U <scat-user>                # lists the allowed commands
   

What this rule does and does not do:

• It only allows reading SMART attributes (-A), nothing else.
• -n standby means: a disk that is spun down stays asleep. scat shows it as SLEEP.
• It only covers disks named sd* and nvme*. Partitions and other devices are not included.

If you prefer not to add the rule, leave the section off: set drives = 0 in settings.conf. With only smartctl -A allowed (no -n standby), scat still works, but it wakes sleeping disks. Details are in the reference.

On OPNsense and other FreeBSD systems, where scat logs in as root, no sudo rule is needed.

Docker, read only

If a server has a docker command, m opens a table of its containers: name, image, status, health, CPU and memory. Running containers come first. The detail view shows the five busiest ones.

scat only reads. It does not start, stop or pull anything, and it does not know about Compose or Podman.

Heads-up: Docker access is root access. Anyone who may use the Docker socket can do anything on that server, so only let scat's user in if that user may have root rights anyway. Details are in the reference.

Temperatures

The list shows the CPU temperature in the TEMP column. scat reads only sensors of the CPU itself. Press f for °F. Setting temp_unit = f makes it the default. Details on which sensors are used are in the reference.

Settings at a glance

Everything lives in ~/.config/scat/. The most useful keys in settings.conf:

Key	Default	What it does
theme	default	colours: default, light, solarized, nord, high-contrast
ping	1	show the ping column in the list
group_headings	1	show group names in the list
temp_unit	c	c or f
drives	1	show the disk section (SMART)
list_refresh	15	seconds between list refreshes

Every key, with its range, is in the reference.

Your passwords stay where they are. scat never reads or stores them. Config files are yours alone (mode 600) and are read as plain data.

Not yet

• Kubernetes pods, planned
• Docker actions (start, stop, logs), not planned for now
• History charts and alerts, not planned for now

More

The full reference, with every measurement, every key and every file, is in docs/reference.md. It covers:

• how the status page is built (CPU, disks, network bars, processes)
• the server list (groups, ping, temperatures)
• every keybinding and every setting
• the Docker and SMART details and their limits
• how scat works and how the tests run

Licence

MIT. See LICENSE. © 2026 d3m0naz.