net-sleep-guard

Prevents your Linux PC from going to sleep while something is downloading. Watches your network speed in real time and holds a systemd-inhibit sleep lock for as long as traffic stays above your threshold. Once the network goes quiet for long enough, it releases the lock and lets the system sleep normally.

  ┌──────────────────────────────────────────────────────┐
  │  ⏻  net-sleep-guard                                  │
  ├──────────────────────────────────────────────────────┤
  │  ↓ Download   24.81 MB/s     ↑ Upload  1.03 MB/s    │
  │  ⇅ Total      25.84 MB/s     ⚑ Limit   2 MB/s       │
  ├──────────────────────────────────────────────────────┤
  │  ████████████████░░░░░░░░░░░░░░░░░░░░░░   42%        │
  │  Cooldown  08:42  until sleep unlocks                │
  ├──────────────────────────────────────────────────────┤
  │  ● Active — sleep blocked                            │
  └──────────────────────────────────────────────────────┘

Requirements

• Linux with systemd (any systemd-based distro — Arch, Garuda, Ubuntu, Fedora, etc.)
• bash 4.0 or newer
• python3 (used to generate the inner worker script cleanly — present by default on virtually all distros)
• systemd-inhibit — part of systemd, already installed if your system uses systemd
• tput — part of ncurses, already installed on virtually all distros
• A terminal that supports UTF-8 and 256 colours (Konsole, GNOME Terminal, Alacritty, kitty, etc.)

Installation

# clone the repo
git clone https://github.com/yourusername/net-sleep-guard.git
cd net-sleep-guard

# make it executable
chmod +x net-sleep-guard.sh

No dependencies to install beyond what ships with your distro.

Usage

./net-sleep-guard.sh

That's it. The script reads its settings from the config block at the top of the file. Press Ctrl-C at any time to release the sleep inhibitor and exit.

Configuration

Open net-sleep-guard.sh in any text editor. The settings are at the very top:

# CONFIGURATION
# THRESHOLD_MBPS  — minimum speed to count as "active". e.g. 1 = 1 MB/s, 0.5 = 500 KB/s
THRESHOLD_MBPS=2
# QUIET_MINUTES   — how long traffic must stay below the threshold before sleep is allowed
QUIET_MINUTES=15
# UNIT            — display unit for speeds. "MB" = megabytes per second (MBps), "Mb" = megabits per second (Mbps)
UNIT="MB"

Setting	Default	Description
THRESHOLD_MBPS	2	Network speed (in your chosen unit) below which traffic is considered idle. Decimals work — 0.5 is valid.
QUIET_MINUTES	15	How many consecutive minutes below the threshold before the sleep lock is released.
UNIT	"MB"	Display unit. "MB" for megabytes/s (what Steam and file managers show). "Mb" for megabits/s (what ISPs advertise — multiply MB/s by 8 to convert).

MB/s vs Mb/s

These are two different ways to measure the same thing:

• MB/s (megabytes per second) — used by Steam, torrent clients, file managers. 1 MB/s = 8 Mb/s.
• Mb/s (megabits per second) — used by ISPs and speed test sites. If your ISP gives you "100 Mbps", that's about 12.5 MB/s.

Set UNIT to match whichever you think in, then set THRESHOLD_MBPS in that unit. The script handles the conversion internally.

How it works

1. On launch, the script registers a sleep inhibitor with systemd-inhibit --mode=block, which prevents the system from sleeping for any reason (suspend, hibernate, idle timeout) while the inhibitor is held.
2. Every second it reads raw byte counters from /proc/net/dev, skipping the loopback interface (lo), and calculates current download and upload speeds.
3. If total speed is above THRESHOLD_MBPS, the countdown timer resets to QUIET_MINUTES.
4. If total speed stays below the threshold for the full QUIET_MINUTES duration, the script exits cleanly — releasing the inhibitor and allowing the system to sleep as normal.
5. Pressing Ctrl-C releases the inhibitor immediately.

You can verify the inhibitor is active while the script is running:

systemd-inhibit --list

You should see a net-sleep-guard entry with the reason shown as the current threshold.

Status indicators

The bottom row of the display shows the current state:

Icon	Colour	Meaning
●	Green	Traffic above threshold — sleep is blocked
◑	Yellow	Traffic dropped below threshold — countdown started, more than halfway remaining
◔	Red	Countdown under halfway — sleep will unlock soon if traffic stays low
○	Red	Countdown reached zero — releasing inhibitor

The progress bar tracks how far through the quiet-time countdown you are. Green means active traffic, yellow means cooling down, red means nearly idle.

License

MIT