witr

Why is this running?

Trace any process, port, container, or file back to the exact chain that started it —
one command, machine-readable JSON, or an interactive TUI.

🎮 Try witr in your browser →

Investigate a simulated Linux box — a guided tutorial and free-play sandbox, no install required.

Purpose • Installation • TUI • Flags • Core Concept • Examples
Output Behavior • Platforms • Success Criteria • Sponsors

1. Purpose

witr exists to answer a single question:

Why is this running?

When something is running on a system, whether it is a process, a service, or something bound to a port, there is always a cause. That cause is often indirect, non-obvious, or spread across multiple layers such as supervisors, containers, services, or shells.

Existing tools (ps, top, lsof, ss, systemctl, docker ps) expose state and metadata. They show what is running, but leave the user to infer why by manually correlating outputs across tools.

witr makes that causality explicit.

It explains where a running thing came from, how it was started, and what chain of systems is responsible for it existing right now, in a single, human-readable output or an interactive TUI dashboard.

📖 Curious how witr came to be? Read the story or browse the Hacker News discussion.

2. Installation

witr is distributed as a single static binary for Linux, macOS, FreeBSD, and Windows.

witr is also independently packaged and maintained across multiple operating systems and ecosystems. An up-to-date overview of packaging status is available on Repology. Please note that community packages may lag GitHub releases due to independent review and validation.

[!TIP] If you use a package manager (Homebrew, Conda, Winget, etc.), we recommend installing via that for easier updates. Otherwise, the install script is the quickest way to get started.

2.1 Quick Install

Unix (Linux, macOS & FreeBSD)

curl -fsSL https://raw.githubusercontent.com/pranshuparmar/witr/main/install.sh | bash

Windows (PowerShell)

irm https://raw.githubusercontent.com/pranshuparmar/witr/main/install.ps1 | iex

2.2 Package Managers

APT (Debian, Ubuntu & Derivatives)

You can install witr from the official Debian and Ubuntu repositories (Ubuntu 26.04+, Debian sid and later), as well as derivative distributions like Kali Linux, Devuan, and Raspbian:

sudo apt install witr

Note: The apt-shipped version may lag the latest GitHub release. For the newest features, use the install script or another installation method.

Homebrew (macOS & Linux)

You can install witr using Homebrew on macOS or Linux:

brew install witr

MacPorts (macOS)

You can install witr using MacPorts on macOS:

sudo port install witr

Conda (macOS, Linux & Windows)

You can install witr using conda, mamba, or pixi on macOS, Linux, and Windows:

conda install -c conda-forge witr
# alternatively using mamba
mamba install -c conda-forge witr
# alternatively using pixi
pixi global install witr

Arch Linux (AUR)

On Arch Linux and derivatives, install from the AUR package:

yay -S witr-bin
# alternatively using paru
paru -S witr-bin
# or use your preferred AUR helper

Winget (Windows)

You can install witr via winget:

winget install -e --id PranshuParmar.witr

NPM (Cross-platform)

You can install witr using npm:

npm install -g @pranshuparmar/witr

FreeBSD Ports

You can install witr on FreeBSD from the FreshPorts port:

pkg install witr
# or
pkg install sysutils/witr

Or build from Ports:

cd /usr/ports/sysutils/witr/
make install clean

Chocolatey (Windows)

You can install witr using Chocolatey:

choco install witr

Scoop (Windows)

You can install witr using Scoop:

scoop install main/witr

AOSC OS

You can install witr from the AOSC OS repository:

oma install witr

GNU Guix

You can install witr from the GNU Guix repository:

guix install witr

Uniget (Linux)

You can install witr using uniget:

uniget install witr

Aqua (macOS, Linux & Windows)

You can install witr using aqua:

# Add package
aqua g -i pranshuparmar/witr

# Install package
aqua i pranshuparmar/witr

Brioche (Linux)

You can install witr using brioche:

brioche install -r witr

Mise (macOS, Linux & Windows)

You can install witr using mise:

mise use github:pranshuparmar/witr

2.3 Source & Manual Installation

go install github.com/pranshuparmar/witr/cmd/witr@latest

# 1. Determine OS and Architecture
OS=$(uname -s | tr '[:upper:]' '[:lower:]')
ARCH=$(uname -m)
[ "$ARCH" = "x86_64" ] && ARCH="amd64"
[ "$ARCH" = "aarch64" ] && ARCH="arm64"

# 2. Download the binary
curl -fsSL "https://github.com/pranshuparmar/witr/releases/latest/download/witr-${OS}-${ARCH}" -o witr

# 3. Verify checksum (Optional)
curl -fsSL "https://github.com/pranshuparmar/witr/releases/latest/download/SHA256SUMS" -o SHA256SUMS
grep "witr-${OS}-${ARCH}" SHA256SUMS | (sha256sum -c - 2>/dev/null || shasum -a 256 -c - 2>/dev/null)
rm SHA256SUMS

# 4. Rename and install
chmod +x witr
sudo mkdir -p /usr/local/bin
sudo mv witr /usr/local/bin/witr

# 5. Install man page (Optional)
sudo mkdir -p /usr/local/share/man/man1
sudo curl -fsSL https://github.com/pranshuparmar/witr/releases/latest/download/witr.1 -o /usr/local/share/man/man1/witr.1

# 1. Determine Architecture
if ($env:PROCESSOR_ARCHITECTURE -eq "AMD64") {
    $ZipName = "witr-windows-amd64.zip"
} elseif ($env:PROCESSOR_ARCHITECTURE -eq "ARM64") {
    $ZipName = "witr-windows-arm64.zip"
} else {
    Write-Error "Unsupported architecture: $($env:PROCESSOR_ARCHITECTURE)"
    exit 1
}

# 2. Download the zip
Invoke-WebRequest -Uri "https://github.com/pranshuparmar/witr/releases/latest/download/$ZipName" -OutFile "witr.zip"
# 3. Extract the binary
Expand-Archive -Path "witr.zip" -DestinationPath "." -Force

# 4. Verify checksum (Optional)
Invoke-WebRequest -Uri "https://github.com/pranshuparmar/witr/releases/latest/download/SHA256SUMS" -OutFile "SHA256SUMS"
$hash = Get-FileHash -Algorithm SHA256 .\witr.zip
$expected = Select-String -Path .\SHA256SUMS -Pattern $ZipName
if ($expected -and $hash.Hash.ToLower() -eq $expected.Line.Split(' ')[0]) { Write-Host "Checksum OK" } else { Write-Host "Checksum Mismatch" }

# 5. Install to local bin directory
$InstallDir = "$env:LocalAppData\witr\bin"
New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
Move-Item .\witr.exe $InstallDir\witr.exe -Force

# 6. Add to User Path (Persistent)
$UserPath = [Environment]::GetEnvironmentVariable("Path", "User")
if ($UserPath -notlike "*$InstallDir*") {
    [Environment]::SetEnvironmentVariable("Path", "$UserPath;$InstallDir", "User")
    $env:Path += ";$InstallDir"
    Write-Host "Added to Path. You may need to restart PowerShell."
}

# 7. Cleanup
Remove-Item witr.zip
Remove-Item SHA256SUMS

2.4 Run Without Installation

nix run github:pranshuparmar/witr -- --help

pixi exec witr --help

2.5 Other Operations

witr --version
man witr

echo 'eval "$(witr completion bash)"' >> ~/.bashrc
source ~/.bashrc

echo 'eval "$(witr completion zsh)"' >> ~/.zshrc
source ~/.zshrc

witr completion fish | source
# To make it permanent:
witr completion fish > ~/.config/fish/completions/witr.fish

witr completion powershell | Out-String | Invoke-Expression
# To make it permanent, add the above line to your $PROFILE

sudo rm -f /usr/local/bin/witr
sudo rm -f /usr/local/share/man/man1/witr.1

Remove-Item -Recurse -Force "$env:LocalAppData\witr"

3. Interactive Mode (TUI)

Running witr without any arguments or with the -i flag launches the Interactive Mode (TUI). This provides a real-time, terminal-based dashboard with four tabs for exploring processes, ports, containers, and file locks.

Key Features:

• Processes Tab: Live, sortable, filterable list of all running processes with a side panel showing the ancestry tree of the highlighted process.
• Ports Tab: Open/listening ports with the owning processes attached in a side panel. Toggle between LISTEN-only and ALL with a.
• Containers Tab: All running containers across Docker, Podman, nerdctl, K8s/crictl, Incus, LXC, LXD, and FreeBSD jails in one list - name, image, status, ports, command, plus a per-container detail view with mounts, networks, and compose project metadata.
• Locks Tab: System-wide file locks (POSIX/FLOCK on Linux, lsof-derived on macOS/FreeBSD). Press a to switch into "all open files" mode, where locked entries are merged with every interesting open fd; type into / to search across the merged set.
• Process Details: Deep-dive into a process to see its full ancestry tree, child processes, environment variables, working directory, sockets, file context, and more.
• Process Actions: Send signals (Kill, Terminate, Pause, Resume) or Renice processes directly from the UI (Unix only).
• Mouse Support: Navigate, sort columns, and click rows using your mouse.
• Adaptive Theme: Colors adapt automatically to light and dark terminal backgrounds.
• Auto-Refresh: The process, port, container, and lock lists refresh automatically on an adaptive cadence (starts at 3 seconds, backing off under load).

4. Flags & Options

  -c, --container strings container(s) to look up (repeatable)
      --env              show environment variables for the process
  -x, --exact            use exact name matching (no substring search)
  -f, --file strings     file(s) held open by a process (repeatable)
  -h, --help             help for witr
  -i, --interactive      interactive mode (TUI)
      --json             show result as JSON
      --no-color         disable colorized output
  -p, --pid strings      pid(s) to look up (repeatable)
  -o, --port strings     port(s) to look up (repeatable)
  -s, --short            show only ancestry
  -t, --tree             show only ancestry as a tree
      --verbose          show extended process information
  -v, --version          version for witr
      --warnings         show only warnings

Positional arguments (without flags) are treated as process or service names. Multiple names can be passed. By default, name matching uses substring matching (fuzzy search). Use --exact to match only processes with the exact name.

All target flags (--pid, --port, --file, --container) are repeatable and can be mixed with each other and with positional name arguments. When multiple targets are provided, results are shown sequentially with labeled dividers. All output modes (standard, short, tree, JSON, env, warnings, verbose) work with multiple inputs.

The --container flag searches across Docker, Podman, nerdctl, K8s/crictl, Incus, LXC, LXD, and FreeBSD jails, and matches against container name, image, command, and compose project/service labels.

The TUI is launched if no arguments or relevant flags (--pid, --port, --file, --container) are provided, or if the --interactive flag is explicitly used.

5. Core Concept

witr treats everything as a process question.

Ports, services, containers, and commands all eventually map to PIDs. Once a PID is identified, witr builds a causal chain explaining why that PID exists.

At its core, witr answers:

1. What is running?
2. How did it start?
3. What is keeping it running?
4. What context does it belong to?

6. Example Outputs

💡 Prefer learning by doing? The interactive browser tutorial walks you through outputs like these live on a simulated box — for a better feel of witr, no install required.

6.1 Name Based Query

witr node

Target      : node

Process     : node (pid 14233)
User        : pm2
Command     : node index.js
Started     : 2 days ago (Mon 2025-02-02 11:42:10 +05:30)

Why It Exists :
  systemd (pid 1) → pm2 (pid 5034) → node (pid 14233)

Source      : pm2

Working Dir : /opt/apps/expense-manager
Git Repo    : expense-manager (main)
Sockets     : 127.0.0.1:5001 (TCP | LISTENING)

6.2 Short Output

witr --port 5000 --short

systemd (pid 1) → PM2 v5.3.1: God (pid 1481580) → python (pid 1482060)

6.3 Tree Output

witr --pid 143895 --tree

systemd (pid 1)
  └─ init-systemd(Ub (pid 2)
    └─ SessionLeader (pid 143858)
      └─ Relay(143860) (pid 143859)
        └─ bash (pid 143860)
          └─ sh (pid 143886)
            └─ node (pid 143895)
              ├─ node (pid 143930)
              ├─ node (pid 144189)
              └─ node (pid 144234)

Note: Tree view includes child processes (up to 10) and highlights the target process.

6.4 Multiple Matches

witr ng

Multiple matching processes found:

[1] nginx (pid 2311)
    nginx -g daemon off;
[2] nginx (pid 24891)
    nginx -g daemon off;
[3] ngrok (pid 14233)
    ngrok http 5000

Re-run with:
  witr --pid <pid>

To avoid substring matching and only find processes with an exact name, use the --exact flag:

witr nginx -x

6.5 File Based Query

witr --file /var/lib/dpkg/lock

Explains the process holding a file open.

6.6 Container Based Query

witr --container redis

Looks up a container by name, image, command, or compose project/service across every detected runtime (Docker, Podman, nerdctl, K8s/crictl, Incus, LXC, LXD, FreeBSD jails). Pass --verbose to include mounts, networks, and compose metadata in the output.

6.7 Multiple Inputs

witr nginx --port 5432 --pid 1234

----- [name: nginx] -----
Target      : nginx
Process     : nginx (pid 2311)
...

----- [port: 5432] -----
Target      : postgres
Process     : postgres (pid 891)
...

----- [pid: 1234] -----
Target      : node
Process     : node (pid 1234)
...

All target flags are repeatable and can be mixed. Results appear in the order you typed them. All output modes (--short, --tree, --json, --env, --warnings, --verbose) work with multiple inputs.

7. Output Behavior

7.1 Output Principles

• Single screen by default (best effort)
• Deterministic ordering
• Narrative-style explanation
• Best-effort detection with explicit uncertainty

7.2 Exit Codes

witr returns meaningful exit codes for use in scripts, CI pipelines, and monitoring:

Example Usage:

witr nginx --short
case $? in
  0) echo "All clear" ;;
  1) echo "Warnings detected" ;;
  2) echo "Process not running" ;;
  3) echo "Need elevated privileges" ;;
  4) echo "Invalid input or ambiguous match" ;;
  5) echo "Internal error" ;;
esac

7.3 Standard Output Sections

Target

What the user asked about.

Process

Executable, PID, user, command, start time and restart count.

Why It Exists

A causal ancestry chain showing how the process came to exist. This is the core value of witr.

Source

The primary system responsible for starting or supervising the process (best effort).

Examples:

• systemd unit with schedule info for timer-triggered services (Linux)
• launchd service with schedule/trigger details (macOS)
• SSH session (with remote IP and terminal)
• docker container
• pm2
• cron
• interactive shell (detects tmux/screen sessions)
• Snap/Flatpak sandbox (Linux)

Only one primary source is selected.

Context (best effort)

• Working directory
• Git repository name and branch
• Container name / image (docker, podman, kubernetes, colima, containerd)
• Public vs private bind

Warnings

Non‑blocking observations such as:

• Process is running as root
• Dangerous Linux capabilities on non-root processes (CAP_SYS_ADMIN, etc.)
• Process is listening on a public interface (0.0.0.0 / ::)
• Restarted multiple times (warning only if above threshold)
• Process is using high memory (>1GB RSS)
• Process has been running for over 90 days
• Deleted binary, library injection indicators (LD_PRELOAD, DYLD_*)

8. Platform Support

• Linux (x86_64, arm64) - Full feature support (/proc).
• macOS (x86_64, arm64) - Uses ps, lsof, sysctl, pgrep.
• Windows (x86_64, arm64) - Native Win32 APIs (ToolHelp32, PSAPI, Service Control Manager). No PowerShell or WMI dependency.
• FreeBSD (x86_64, arm64) - Uses procstat, ps, lsof.

8.1 Feature Compatibility Matrix

Legend: ✅ Full support | ⚠️ Partial/limited support | ❌ Not available

8.2 Permissions Note

Linux/FreeBSD

witr inspects system directories which may require elevated permissions.

If you are not seeing the expected information, try running witr with sudo:

sudo witr [your arguments]

macOS

On macOS, witr uses ps, lsof, and launchctl to gather process information. Some operations may require elevated permissions:

sudo witr [your arguments]

Note: Due to macOS System Integrity Protection (SIP), some system process details may not be accessible even with sudo.

Windows

On Windows, witr talks directly to Win32 APIs (ToolHelp32, PSAPI, Service Control Manager) rather than spawning PowerShell or WMI, startup is fast and there's no Get-CimInstance hang. To see details for processes owned by other users or system services, you must run the terminal as Administrator.

# Run in Administrator PowerShell
.\witr.exe [your arguments]

9. Success Criteria

witr is successful if:

• A user can answer "why is this running?" within seconds
• It reduces reliance on multiple tools
• Output is understandable under stress
• Users trust it during incidents

10. Sponsors

Special thanks to the people who supported witr ❤️