Charm Vhs

charm-vhs

VHS records terminal sessions from .tape scripts. Requires ttyd and ffmpeg on PATH.

brew install vhs       # also installs deps on macOS
vhs demo.tape          # run a tape file
vhs new demo.tape      # scaffold a new tape
vhs record > out.tape  # record interactively, then exit
vhs publish demo.gif   # host on vhs.charm.sh

Tape File Structure

Order matters: Output and Set must come before action commands. Require goes at the very top.

Require <program>   # fail early if missing from PATH
Output <path>       # .gif / .mp4 / .webm / .ascii / frames/
Set <Setting> Value # terminal config (must precede actions)
<actions>           # Type, Enter, Sleep, etc.

Output Formats

Output demo.gif
Output demo.mp4
Output demo.webm
Output frames/        # PNG sequence
Output golden.ascii   # for CI golden file diffing

Multiple Output lines are fine - all render in one run.

Settings Reference

Set Shell "zsh"
Set FontSize 14
Set FontFamily "JetBrains Mono"
Set Width 1200
Set Height 600
Set Padding 20
Set Margin 40
Set MarginFill "#6B50FF"
Set BorderRadius 10
Set WindowBar Colorful        # Colorful, ColorfulRight, Rings, RingsRight
Set Theme "Catppuccin Frappe" # run `vhs themes` for full list
Set TypingSpeed 0.05          # seconds per keypress
Set Framerate 60
Set PlaybackSpeed 1.0
Set LoopOffset 50%            # where GIF loop starts
Set CursorBlink false

TypingSpeed is the only setting that can change mid-tape. All others are ignored after the first action command.

Action Commands

Typing + input

Type "git status"           # types the string
Type@500ms "slowly..."      # override typing speed for this line
Type `VAR="backtick escapes quotes"`
Enter
Enter 2                     # press N times
Tab
Tab@200ms 3
Backspace 5
Space 2

Navigation

Up / Down / Left / Right    # arrow keys
Up 3                        # repeat N times
PageUp / PageDown
ScrollUp 10
ScrollDown@100ms 5
Ctrl+C
Ctrl+Alt+Delete

Timing

Sleep 500ms
Sleep 2s
Sleep 0.5       # seconds (float ok)
Wait /regex/    # wait until last line matches (default timeout 15s)
Wait+Screen /regex/         # check whole screen
Wait+Line@10ms /regex/      # poll every 10ms

Wait is better than Sleep for commands with unpredictable runtime (builds, network calls).

Hide / Show

Hide
Type "setup stuff not shown in recording"
Enter
Wait /\$/
Show

Use Hide/Show to run setup or cleanup without polluting the demo.

Other

Screenshot path/out.png     # capture current frame as PNG
Copy "text"                 # put text on clipboard
Paste                       # paste clipboard
Env KEY "value"             # set env var
Source config.tape          # include another tape

Example Tapes

1. Simple CLI demo

Output demo.gif

Set FontSize 14
Set Width 900
Set Height 400
Set Theme "Catppuccin Frappe"
Set WindowBar Colorful
Set TypingSpeed 0.05

Type "ls -la"
Sleep 300ms
Enter
Sleep 2s

2. Build + run with hidden setup

Output demo.gif

Set FontSize 13
Set Width 1200
Set Height 600
Set Theme "Dracula"

Require go

Hide
Type "go build -o myapp . && clear"
Enter
Wait /\$/
Show

Type "./myapp --help"
Sleep 200ms
Enter
Sleep 3s

Hide
Type "rm myapp"
Enter

3. Interactive TUI demo with Wait

Output tui-demo.gif
Output tui-demo.mp4

Set FontSize 14
Set Width 1000
Set Height 500
Set WindowBar Rings
Set Margin 30
Set MarginFill "#1a1b26"
Set BorderRadius 8
Set TypingSpeed 0.07

Require gum

Type "gum choose 'Option A' 'Option B' 'Option C'"
Enter
Sleep 500ms
Down
Sleep 300ms
Down
Sleep 500ms
Enter
Sleep 2s

CI Integration

Use the vhs-action GitHub Action to regenerate GIFs on push.

For integration testing, output .ascii and commit as golden files - diff them in CI to catch terminal output regressions.

Output golden.ascii

Tips

• vhs record > cassette.tape then edit the generated tape to add Set blocks and clean up timing
• Use Source to share a config.tape with common Set defaults across multiple tapes
• Wait beats Sleep for anything async - no need to guess how long a build takes
• LoopOffset makes the GIF preview frame more interesting than frame 0
• vhs themes lists all built-in theme names