gander

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A cross-platform interactive process viewer written in Rust.

gander shows what is running on your system and how much it costs. It supports Linux, macOS and FreeBSD, keeps most htop keybindings, and provides a process-focused layout with a persistent inspector.

Features

• Process-first layout. The default panels layout combines a compact system column, a wide process table and a live inspector. Press L to switch to the classic htop layout.
• Inspect without leaving the list. Command line, state, memory and runtime update with the selected process.
• Responsive sampling. Sampling runs in the background while the renderer reads a snapshot.
• Scriptable output. --json, -n, --sort, --filter and --limit work without the TUI.
• Linux depth. PSS/EPSS, PSI, zram/zswap, GPU, delay accounting and container identity are available as optional columns or meters.
• Native backends. Linux uses /proc, macOS uses sysctl/Mach/libproc, and FreeBSD uses sysctl/libkvm.

Platform support

Other Unix targets may compile but have no live backend. See docs/PORTABILITY.md for details.

Install

Prebuilt binaries

Download the archive for your platform from GitHub Releases.

.deb and .rpm packages are published beside the archives for Linux x86_64 and arm64; see Debian/Ubuntu and Fedora/RHEL.

tar -xzf gander-<version>-<target>.tar.gz
./gander-<version>-<target>/gander

To install it on your PATH:

mkdir -p ~/.local/bin
install -m755 gander-<version>-<target>/gander ~/.local/bin/gander

The musl build is static and does not depend on the host's glibc. Each archive has a .sha256 checksum file.

Debian/Ubuntu and Fedora/RHEL

Both distributions have a signed repository, so apt and dnf install and upgrade gander like any other package.

# Debian, Ubuntu, Linux Mint, …
sudo mkdir -p /usr/share/keyrings
curl -fsSL https://pandasir.github.io/gander/gander.gpg \
  | sudo gpg --dearmor -o /usr/share/keyrings/gander.gpg
echo "deb [signed-by=/usr/share/keyrings/gander.gpg] https://pandasir.github.io/gander stable main" \
  | sudo tee /etc/apt/sources.list.d/gander.list
sudo apt update && sudo apt install gander

# Fedora, RHEL, Rocky, Alma, openSUSE, …
sudo rpm --import https://pandasir.github.io/gander/RPM-GPG-KEY-gander
sudo curl -fsSL https://pandasir.github.io/gander/gander.repo \
  -o /etc/yum.repos.d/gander.repo
sudo dnf install gander

Upgrades then arrive with apt upgrade / dnf upgrade. The repositories are signed and the clients verify them: apt checks InRelease, and dnf runs with gpgcheck=1 and repo_gpgcheck=1.

If you would rather not add a repository, the release still ships the packages as files:

sudo apt install ./gander_<version>-1_amd64.deb      # arm64 on ARM machines
sudo dnf install ./gander-<version>-1.x86_64.rpm     # aarch64 on ARM machines

SHA256SUMS beside them covers every package.

Package managers

The crates.io package is named gander-bin because gander is already taken by an unrelated crate; the installed command is still gander.

From source

Requires Rust 1.89+. No ncurses or libcurses development headers are needed.

git clone https://github.com/pandasir/gander
cd gander
cargo install --locked --path crates/bin

Or run it without installing:

cargo run --release -p gander-bin

Quick start

gander                                     # interactive TUI
gander --delay 500                         # sample every 500 ms
gander -n 5 -d 1000                        # five text samples
gander --json --limit 10                   # one JSON sample
gander --sort PERCENT_MEM --limit 20       # top 20 by memory
gander -F "python|node"                    # filter command lines
gander --import-htoprc ~/.config/htop/htoprc --save

Filter terms are case-insensitive fixed strings separated by |; they are not regular expressions. Run gander --help for all options.

Interface and keys

panels is the default layout: a system column on the left, the process table in the center and an inspector on the right. htop is the classic full-width layout. L switches between them and the choice is saved.

Keys that differ from htop:

htop's I inverts the sort order; in gander use F6 / < > / . instead. See docs/KEYS.md for the complete keymap.

Configuration

Configuration is TOML at $GANDER_CONFIG, otherwise $XDG_CONFIG_HOME/gander/config.toml (fallback: ~/.config/gander/config.toml). Each tab keeps its own columns and sort order; header meters and their display modes are configurable. Settings are saved on a clean exit. A missing file uses defaults; unreadable, malformed or invalid settings produce an error without overwriting the file. Saves replace the file atomically.

system_cores_max caps the per-core grid in the panels system column. 0, the default, draws every core the column has room for; on a short terminal the grid stops early and the label reads 64/128 cores so a truncated grid cannot be mistaken for a 64-core machine. F2 -> Display cycles the same setting.

Search and filter history is stored under $XDG_STATE_HOME/gander/ (fallback: ~/.local/state/gander/).

Available themes: gander, default, monochrome, midnight, classic, verdant, paper and quiet. Choose one from F2 -> Colors or set color_scheme in the config.

Linux depth

• M_PSS, M_EPSS, M_PRIVATE, M_SWAP: read on demand from smaps_rollup; unmeasured values show -, not 0.
• GPU%, GPU_TIME: read from drm-usage-stats without a vendor SDK.
• CPUD%, IOD%, SWPD%: TASKSTATS delay accounting; requires CAP_NET_ADMIN.
• CONTAINER, CGROUP: cgroup path combined with PID namespace detection.
• PSI, Zram, Zswap, HugePages: optional header meters.

Use F2 -> Columns or F2 -> Header to enable them. See docs/DESIGN.md and docs/PORTABILITY.md for implementation details.

Development

The workspace is split into four crates:

cargo build --locked
cargo test --locked --workspace
cargo clippy --locked --workspace --all-targets -- -D warnings
cargo bench -p gander-core

Live macOS tests read the system process table and may need to run outside a restricted sandbox. See CONTRIBUTING.md for the full development and review workflow.

Documentation

Contributing

Bug reports, platform observations and focused pull requests are welcome. Start with CONTRIBUTING.md. Report security vulnerabilities privately according to SECURITY.md; do not open a public issue.

License

GPL-2.0-or-later. Behaviour, keybindings and column semantics are derived from htop; keep the license compatible and credit it.