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btop — Modern Terminal Resource Monitor

Complete beginner guide to btop, monitoring CPU cores, memory, swap, disk I/O, network bandwidth, process inspection, and sending kill signals from your terminal.

3 min read Last updated: 2026-10-06
GitHub
btop monitoring linux sysadmin terminal performance
On this page
  1. What is btop?
  2. Installation
  3. Running btop and CLI Flags Breakdown
  4. CLI Flag breakdown
  5. Essential In-App Keyboard Shortcuts
  6. Understanding System Metrics
  7. 1. Load Average (1m, 5m, 15m)
  8. 2. RAM vs. Buffers / Cache
  9. 3. Swap Usage

What is btop?

When investigating high server loads or sluggish systems, traditional tools like top feel archaic and hard to read.

btop (the high-performance C++ successor to bpytop and bashtop) is an interactive, responsive terminal resource monitor. It visualizes:

  1. CPU Usage & Temperatures: Per-core frequency, utilization graphs, and system load averages.
  2. Memory & Swap: Physical RAM utilization, disk cache buffers, and swap pressure.
  3. Disks & Storage I/O: Real-time read/write speeds, free space percentages, and active mounts.
  4. Network Activity: Real-time upload and download rate graphs with total bandwidth counters.
  5. Interactive Process Explorer: Search, filter, inspect process trees, and terminate runaway processes.

Installation

On modern Linux distributions:

bash
# Ubuntu 22.04+ / Debian 12+
sudo apt update
sudo apt install -y btop

# Fedora / RHEL
sudo dnf install -y btop

# Arch Linux
sudo pacman -S btop

Running btop and CLI Flags Breakdown

bash
# Launch interactive monitor
btop

# Launch with a specific layout preset (Presets 0 to 4)
btop -p 1

# Launch in low-color mode (for basic TTYs or serial consoles)
btop --low-color

CLI Flag breakdown

  • -p <number> (or --preset): Loads a specific preset layout (e.g., CPU-only, processes-only, or full 4-panel dashboard).
  • --low-color: Restricts rendering to standard 16-color ANSI output for legacy terminal emulators or low-bandwidth serial connections.
  • --utf-force: Forces UTF-8 symbols even if locale detection reports ASCII.

Essential In-App Keyboard Shortcuts

Navigate btop effortlessly with your keyboard or mouse:

KeyAction
m or EscOpen main menu (Options, Help, Themes, Quit)
qInstantly quit btop
Up / DownScroll through the running process list
fFilter / search processes by name (press Enter to confirm, Esc to clear)
tToggle process Tree View (visualize parent and child processes)
kSend SIGKILL (-9) to force-kill the highlighted runaway process
sSend custom termination signals (SIGTERM, SIGHUP, SIGINT)
+ / -Increase or decrease refresh interval speed (100ms to 2000ms)
1 / 2 / 3 / 4Toggle display of CPU, Memory, Disks, or Processes panels

Understanding System Metrics

1. Load Average (1m, 5m, 15m)

Displayed at the top of the CPU box:

  • Represents the average number of processes actively using or waiting for CPU time over 1, 5, and 15 minutes.
  • On an 8-core CPU, a load average below 8.0 means the system has surplus capacity. A load average of 16.0 means tasks are queued up and waiting.

2. RAM vs. Buffers / Cache

Linux aggressively uses free RAM to cache disk reads (Cached). If btop shows high memory usage but low swap, do not panic! Linux automatically reclaims cached RAM the millisecond an application requests it.

3. Swap Usage

If swap usage is rising alongside high disk I/O, the system is low on physical RAM and thrashing the disk.