vhs（录像带）

VHS — Terminal Recorder

VHS records terminal sessions from declarative .tape files. Produces GIF, MP4, or WebM. No screen recording needed — deterministic and reproducible.

Install

scoop install vhs    # Windows
brew install vhs     # macOS

Requires ffmpeg (for video encoding). scoop install ffmpeg if missing.

Quick Start

# Create example tape
vhs new demo.tape

# Record
vhs demo.tape

# Validate without running
vhs validate demo.tape

# Publish to vhs.charm.sh (get shareable URL)
vhs publish demo.gif

Tape File Syntax

Output

Output demo.gif                    # GIF (default, best for READMEs)
Output demo.mp4                    # MP4 video
Output demo.webm                   # WebM video

Multiple Output lines = multiple formats from one tape.

Settings

Set Shell "bash"                   # Shell to use
Set FontSize 14                    # Font size (default 22 — too large for most)
Set FontFamily "JetBrains Mono"    # Font family
Set Width 1200                     # Terminal width in pixels
Set Height 600                     # Terminal height in pixels
Set Padding 15                     # Padding around terminal
Set TypingSpeed 50ms               # Delay between keystrokes (default 50ms)
Set Theme "Dracula"                # Color theme (see Themes below)
Set Framerate 30                   # GIF framerate
Set PlaybackSpeed 1.0              # Playback speed multiplier
Set LoopOffset 80%                 # Where GIF loop restarts (% from end)
Set WindowBar "Colorful"           # Window bar: Rings, RingsRight, Colorful, ColorfulRight
Set WindowBarSize 40               # Window bar height in pixels
Set BorderRadius 8                 # Terminal border radius
Set MarginFill "#1a1a2e"           # Background color outside terminal
Set Margin 20                      # Margin size (needs MarginFill)

Commands

Type "echo hello"                  # Type characters
Type@100ms "slow typing"           # Type with custom speed
Enter                              # Press Enter
Enter 3                            # Press Enter 3 times
Sleep 2s                           # Wait 2 seconds
Sleep 500ms                        # Wait 500 milliseconds

# Special keys
Backspace 5                        # Delete 5 chars
Tab                                # Tab completion
Ctrl+C                             # Interrupt
Ctrl+L                             # Clear screen
Up                                 # Arrow up (history)
Down                               # Arrow down
Left 3                             # Move cursor left 3
Right 3                            # Move cursor right 3
Escape                             # Escape key
Space                              # Space key
PageUp                             # Page up
PageDown                           # Page down

# Visibility
Hide                               # Hide commands from output
Show                               # Show commands again

Require

Require git                        # Fail if git not in PATH
Require node

Windows: Use Set Shell "cmd"

VHS's default bash resolves to WSL bash on Windows — a separate environment with no access to Windows-installed tools (node, scoop packages, etc.). Always use cmd on Windows:

Set Shell "cmd"

This gives VHS the full Windows PATH so all installed CLIs work.

Recommended Defaults

For README demos and documentation:

Output demo.gif
Set Shell "cmd"                    # Windows — use "bash" on Linux/macOS
Set FontSize 14
Set Width 1100
Set Height 600
Set Theme "Dracula"
Set TypingSpeed 30ms
Set Padding 15
Set WindowBar "Colorful"
Set BorderRadius 8

Patterns

Simple command showcase

Output demo.gif
Set Shell "bash"
Set FontSize 14
Set Width 1100
Set Height 600
Set Theme "Dracula"
Set TypingSpeed 30ms
Set Padding 15

Type "my-tool --help"
Enter
Sleep 3s

Type "my-tool run --input data.json"
Enter
Sleep 5s

Complex commands (use a wrapper script)

VHS tape files don't support shell quoting well. For complex commands with quotes, pipes, or multi-line args, write a helper script:

# demo-run.sh
#!/bin/bash
echo "Running analysis..."
my-tool analyze --format json | jq '.results[] | .name'

Type "bash demo-run.sh"
Enter
Sleep 10s

Hide setup, show the interesting part

# Setup (hidden from recording)
Hide
Type "cd /tmp/demo-project"
Enter
Type "export DEMO_MODE=1"
Enter
Sleep 1s
Show

# Visible demo starts here
Type "my-tool init"
Enter
Sleep 3s

Before/after comparison

Type "# Before:"
Enter
Type "cat config.yaml"
Enter
Sleep 3s

Type "# After running fix:"
Enter
Type "my-tool fix config.yaml"
Enter
Sleep 3s

Type "cat config.yaml"
Enter
Sleep 3s

Recording live (interactive)

# Record your terminal actions into a tape file
vhs record > my-session.tape
# Then edit the tape to clean up timing, add sleeps, etc.
vhs my-session.tape

Recording TUI apps with holdpty

Use holdpty to record full-color TUI applications — apps that need a real PTY for colors, take time to start, or are already running. holdpty provides the PTY, VHS captures the output.

Why this matters:

• TUI apps (pi, htop, k9s, lazygit) need a real PTY for colors and layout
• Slow-starting apps (AI agents, servers) can be ready before recording begins
• Already-running processes can be recorded on demand for monitoring/sharing

The pattern:

# Step 1: Launch the app in holdpty (or it's already running)
holdpty launch --bg --name demo -- my-tui-app

# Step 2: Wait for it to be ready (or it already is)
sleep 5

# Step 3: Record with VHS
vhs record-demo.tape

# Step 4: Clean up (or leave it running)
holdpty stop demo

Tape file — attach to a running session:

Output demo.gif
Output demo.mp4
Set Shell "cmd"
Set FontSize 14
Set Width 1200
Set Height 700
Set Theme "Dracula"
Set Padding 15
Set WindowBar "Colorful"
Set BorderRadius 8

# Attach to the running holdpty session
Type "holdpty attach demo"
Enter
Sleep 2s

# Interact with the app (VHS types, app responds with full TUI)
Type "your input here"
Enter
Sleep 15s

Tape file — view-only snapshot of a running process:

Output snapshot.gif
Set Shell "cmd"
Set FontSize 14
Set Width 1200
Set Height 700
Set Theme "Dracula"
Set Padding 15

# View is read-only — just captures current output
Type "holdpty view demo"
Enter
Sleep 10s
Ctrl+C

Use cases:

• README demos — launch app, let it start, record the interesting part
• Monitoring snapshots — capture what a running service looks like right now
• Bug reports — record a live reproduction with full colors
• Agent recordings — capture an AI agent working with its full TUI (thinking indicators, tool calls, colored output)

On Windows, use node.exe <path/to/cli.js> instead of CLI names when launching via holdpty — see the holdpty skill for the .cmd wrapper gotcha.

Themes

Popular themes for demos:

List all: vhs themes

Tips

1. FontSize 14 — default 22 is way too large for most demos
2. TypingSpeed 25-40ms — 50ms default feels slow; 25ms is snappy
3. Sleep after Enter — always add Sleep after commands to let output render
4. Long commands — use wrapper scripts, VHS quoting is fragile
5. GIF size — keep under 5MB for GitHub READMEs; reduce Framerate, Height, or duration
6. Multiple outputs — one tape can produce .gif + .mp4 simultaneously
7. Publish — vhs publish demo.gif gives a shareable URL on vhs.charm.sh
8. Validate first — vhs validate demo.tape catches syntax errors without recording

Gotchas

• Windows: Set Shell "bash" uses WSL — VHS resolves bash to WSL bash, not Git Bash. Use Set Shell "cmd" to get the full Windows PATH. Custom shell paths (Set Shell "C:/path/to/bash.exe") are rejected.
• No shell expansion in Type — Type "echo $HOME" types the literal string; variable expansion happens when bash executes it, not in the tape
• Quoting — avoid nested quotes in Type. Use wrapper scripts for complex commands
• Windows paths — use forward slashes in Type strings (C:/dev/... not C:\dev\...)
• Long recordings — GIFs get huge fast. Keep demos under 30 seconds. Use Set PlaybackSpeed 2.0 to compress
• Terminal size — if output wraps weird, increase Width or reduce FontSize
• TUI apps without holdpty — apps that need a real PTY for colors (pi, htop, lazygit) will render without colors if launched directly from VHS. Use the holdpty pattern above.