wsl-screenshot-cli

CLI tool that monitors the Windows clipboard for screenshots, making them pasteable in WSL (e.g. Claude Code CLI, Codex CLI, ...) while preserving Windows paste functionality.

Take a screenshot on Windows, then paste in your WSL terminal — you get a file path. Paste in Paint — you get the image. Paste in Explorer — you get the file. All at the same time.

Quick Start

wsl-screenshot-cli start --daemon   # start monitoring
wsl-screenshot-cli status           # check it's running
wsl-screenshot-cli stop             # stop monitoring
wsl-screenshot-cli update           # update to latest version

Installation

Quick install (recommended)

curl -fsSL https://nailu.dev/wscli/install.sh | bash

This downloads the latest binary to ~/.local/bin/. No Go toolchain required.

Via Go

go install github.com/nailuu/wsl-screenshot-cli@latest

From source

git clone https://github.com/Nailuu/wsl-screenshot-cli.git
cd wsl-screenshot-cli
go build -o wsl-screenshot-cli .

Auto-start options

Option 1 — Auto-start with your shell (add to ~/.bashrc or ~/.zshrc):

wsl-screenshot-cli start --daemon --quiet

Tip: The --quiet flag prevents the Polling process is already running message from appearing each time you open a new terminal.

Note: The install script places the binary in ~/.local/bin/, which is typically added to PATH by ~/.profile (login shells only). If you get command not found in .bashrc, add this before the line above: bash if [ -d "$HOME/.local/bin" ] && [[ ":$PATH:" != *":$HOME/.local/bin:"* ]]; then export PATH="$HOME/.local/bin:$PATH" fi

Option 2 — Auto-start/stop with Claude Code hooks (add to ~/.claude/settings.json):

{
  "hooks": {
    "SessionStart": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "command",
            "command": "wsl-screenshot-cli start --daemon --quiet 2>/dev/null; echo 'wsl-screenshot-cli started'"
          }
        ]
      }
    ],
    "SessionEnd": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "command",
            "command": "wsl-screenshot-cli stop 2>/dev/null"
          }
        ]
      }
    ]
  }
}

How It Works

graph LR
    subgraph WSL
        CLI["wsl-screenshot-cli"]
        Poller
        GoClient["Clipboard Client"]
    end

    subgraph Windows
        PS["PowerShell · STA"]
        DotNet[".NET Clipboard API"]
        CB["Clipboard"]
    end

    subgraph Output
        PNG["SHA256.png"]
    end

    CLI -- "start / stop / status" --> Poller
    Poller -- "poll every 250ms" --> GoClient
    GoClient -- "stdin / stdout" --> PS
    PS -- "CHECK" --> DotNet
    DotNet -- "read image" --> CB
    Poller -- "save & dedup" --> PNG

A persistent powershell.exe -STA subprocess handles all clipboard access via a simple stdin/stdout text protocol (CHECK / UPDATE / EXIT). The Go side polls by sending CHECK commands; PowerShell uses pre-compiled .NET Clipboard APIs (System.Windows.Forms.Clipboard) for change detection — no runtime C# compilation, so it works even when EDR products (SentinelOne, CrowdStrike, etc.) block csc.exe. DoEvents() pumps Windows messages to keep the STA thread responsive — preventing freezes in Explorer, Snipping Tool, and other apps during clipboard operations.

When a new screenshot is detected, the poller:

1. Receives the image as base64 PNG from PowerShell
2. Deduplicates by SHA256 hash and saves to disk
3. Converts the WSL path to a Windows path via wslpath -w
4. Tells PowerShell to set three clipboard formats at once

What Happens When You Paste

After a screenshot is captured, the clipboard contains three formats simultaneously:

Usage

Start

# Foreground (useful for debugging)
wsl-screenshot-cli start

# Background daemon (typical usage)
wsl-screenshot-cli start --daemon

# Custom interval and output directory
wsl-screenshot-cli start --daemon --interval 1000 --output ~/screenshots/

# Debug mode — logs all PowerShell I/O
wsl-screenshot-cli start --verbose

Status

$ wsl-screenshot-cli status
Status:       running
PID:          12345
Uptime:       2h 15m 30s
CPU usage:    2.5%
Memory:       45.2 MB
Screenshots:  127
Output dir:   /tmp/.wsl-screenshot-cli/
Log file:     /tmp/.wsl-screenshot-cli.log

Stop

wsl-screenshot-cli stop

Update

wsl-screenshot-cli update

Updates to the latest release from GitHub. If the daemon is running, it will be stopped before updating. Re-running the install script when already on the latest version will skip the download.

Prerequisites

• WSL2 with Windows interop enabled
• PowerShell accessible from WSL (powershell.exe must be in PATH)
• Go 1.25+ (only if building from source)

Tests

Requirements

• Go 1.25+
• gcc — required for the -race flag (cgo dependency). Install with: bash sudo apt update && sudo apt install -y gcc

Running tests

Run the full suite with the race detector:

CGO_ENABLED=1 go test -race -count=1 -v ./...

Without gcc, you can still run tests without race detection:

go test -count=1 -v ./...

Project Structure

├── main.go                        # Entry point
├── cmd/
│   ├── root.go                    # Root cobra command
│   ├── start.go                   # start command (flags, daemon/foreground)
│   ├── status.go                  # status command (process diagnostics)
│   ├── stop.go                    # stop command (SIGTERM)
│   └── update.go                  # update command (self-update via install script)
└── internal/
    ├── clipboard/
    │   ├── clipboard.go           # Go ↔ PowerShell client (stdin/stdout pipes)
    │   └── clipboard.ps1          # Embedded PowerShell script (Win32 clipboard)
    ├── daemon/
    │   ├── daemon.go              # Daemonize, PID management, lifecycle
    │   └── status.go              # /proc parsing (CPU, memory, uptime)
    ├── platform/
    │   └── platform.go            # WSL environment checks
    └── poller/
        └── poller.go              # Poll loop, SHA256 dedup, circuit breaker