Svelte Bash

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Svelte Bash is a terminal emulator component for Svelte 5. It has a virtual file system, a small real shell (quotes, pipes, redirects, aliases), command history, themes, an in-terminal nano, scripted demos, and a one-call portfolio mode.

New here? Open the live examples: each one has a working terminal and code you can copy.

It uses plain scoped CSS: you do not need Tailwind or any other CSS framework.

Themes

Pick one with a single prop: <Terminal theme="dracula" />. Nine presets are built in, and you can pass your own colors. See Theming.

Key features

• Portfolio mode: createPortfolio({...}) gives you about, projects, skills, contact, open, neofetch and more.
• A real little shell: ls cat cd pwd echo mkdir touch rm cp mv alias unalias grep head tail wc find tree man history theme nano clear, plus |, >, >>, ;, && and quoting.
• Virtual file system that is never mutated (your object is copied) and can be persisted to localStorage.
• Window chrome: macOS, Linux or Windows style title bars.
• 9 themes and CSS variables for everything else.
• Autoplay / bootplay / typewriter for landing pages and docs. Autoplay really runs the commands.
• Ghost completion, ZSH-style syntax highlighting, Tab completion for commands, paths and aliases.
• Accessible and mobile friendly: role="log", labelled input, on-screen Tab/arrow keys (mobileKeys).
• Fully typed and covered by 260+ tests.

Installation

npm install svelte-bash

Requires Svelte 5.

Portfolio in 30 seconds

<script>
  import { Terminal, createPortfolio } from 'svelte-bash';

  const portfolio = createPortfolio({
    name: 'Ada Lovelace',
    role: 'Software Engineer',
    location: 'London',
    about: 'I build fast, accessible web apps.',
    skills: { Frontend: ['Svelte', 'TypeScript'], Backend: ['Node.js'] },
    projects: [
      { name: 'My App', description: 'Something cool', url: 'https://example.com', tags: ['svelte'] }
    ],
    links: { github: 'https://github.com/you', linkedin: 'https://linkedin.com/in/you' },
    email: '[email protected]',
    resumeUrl: 'https://example.com/cv.pdf'
  });
</script>

<Terminal
  {...portfolio}
  windowStyle="macos"
  title="you — zsh"
  theme="tokyo-night"
  ghostCompletion
  syntaxHighlight
  style="height: 480px"
/>

Visitors can type about, projects, projects my-app, skills, contact, open github, resume, neofetch, cat projects/my-app.md, tree or theme nord.

createPortfolio option	Description
name (required), role, location	Shown in the welcome message, README.md, neofetch.
about	String or array of lines (about, about.txt).
skills	string[] or { group: string[] }.
projects	{ name, description, url?, tags? }[], also written to projects/<slug>.md.
links, email, resumeUrl	Used by contact, links, open, resume.
files, commands, welcome	Extra files, extra/override commands, custom welcome lines.

open and resume only open http(s): and mailto: URLs, in a new tab with noopener,noreferrer.

Basic usage

<script>
  import { Terminal } from 'svelte-bash';

  const files = {
    'readme.md': '# Hello World',
    src: { 'app.js': 'console.log("Hi")' }
  };
</script>

<Terminal structure={files} user="guest" style="height: 300px" />

The component fills its parent: give it (or its parent) a height.

Custom commands

<script>
  const commands = {
    hello: () => 'Hello from svelte-bash!',
    shout: (args, ctx) => (ctx.stdin ?? args.join(' ')).toUpperCase(),
    time: async () => new Date().toLocaleTimeString(),
    chart: () => MyChartComponent            // return a Svelte component to render it
  };
</script>

<Terminal {commands} />

Give a command a description and it shows up in help and answers --help:

<script>
  const commands = {
    hello: {
      description: 'Say hello',
      usage: 'hello [name]',
      run: (args) => `Hello ${args[0] ?? 'world'}!`
    }
  };
</script>

Handlers get (args, { stdin, cwd, user }). Return a string, string array, number, a Svelte component, or nothing. Thrown errors are printed as errors. Custom commands take priority over built-ins and work in pipes: echo hi | shout.

Persistence

<Terminal structure={initial} persist="my-site-terminal" />

The whole file system is saved to localStorage under that key and restored on the next visit (it replaces structure, so deleted files stay deleted). persist={true} uses the key svelte-bash-fs. Storage errors never break the terminal.

Controlling the terminal

<script>
  let term;
</script>

<Terminal bind:this={term} />
<button onclick={() => term.run('ls -la')}>Run ls</button>

Method	Description
run(command)	Execute a line as if typed.
clear()	Clear the screen.
focus()	Focus the input.
reset()	Restore the initial file system and clear the screen.
getStructure()	Copy of the current file system.

Autoplay and bootplay

<Terminal
  autoplay={[
    { command: 'mkdir project' },
    { command: 'echo "hello" > project/hi.txt', delayAfter: 500 },
    { command: 'tree' },
    { command: 'deploy', output: 'Shipped! 🚀' }   // fixed output instead of running
  ]}
  typingSpeed={60}
/>

<Terminal bootplay={[{ output: 'Booting…' }, { output: 'Ready.', delay: 400 }]} />

Without output, the command is actually executed. When the script loops, the screen and file system are reset. All timers stop when the component is destroyed.

Shell reference

Command	Notes
ls [-a] [-l] [-1] [path…]	Hidden files with -a.
cat [-n] [file…]	Reads stdin when piped.
cd, pwd	cd, cd ~, cd .., absolute and ~/ paths.
echo, mkdir [-p], touch	Several arguments allowed.
rm [-r] [-f], cp [-r], mv	Several sources into a directory. Refuses unsafe moves.
grep [-i -v -n -c] pattern [file…]	JavaScript regular expressions.
head, tail (-n N or -N), wc [-l -w -c]	Files or stdin.
find [path] [-name glob] [-type f|d], tree [path]
alias, unalias, history, clear, man, help, whoami, date
theme [name]	List or switch themes at runtime.
nano <file>	^X saves and exits, ^C / Esc cancels.

Operators: a | b, a > file, a >> file, a; b, a && b. Quotes ("…", '…') and \ escapes are supported.

Keyboard: Tab completes, ↑/↓ history, Ctrl+L clear, Ctrl+C cancel line (copies if text is selected).

Customize

Every option is a prop. Use <user>, <host>, <cwd>, <path> (or {user} inside a JS string) as tokens.

<Terminal
  promptFormat="<user>@<host>:<cwd>$"
  placeholder="Type 'help'"
  cursorStyle="bar"
  visualEffect="crt"
  fontFamily="'JetBrains Mono', monospace"
  fontSize={15}
  helpMessage="Try: about, projects, contact"
  notFoundMessage="Sorry, <cmd> is not a thing here."
  disabledCommands={['rm', 'mv']}
  maxLines={500}
/>

promptFormat may also be a function (ctx) => string with ctx = { user, host, cwd, path }. visualEffect is 'none' | 'glow' | 'scanlines' | 'crt'. cursorStyle is 'block' | 'bar' | 'underline'. Animations respect prefers-reduced-motion. Shortcuts: Ctrl+A / Ctrl+E start / end of line, Ctrl+U clear line, Ctrl+L clear screen, Ctrl+C cancel (or copy a selection).

More colour variables: --sb-error, --sb-muted, --sb-cmd, --sb-bad, --sb-flag, --sb-str, --sb-op, --sb-font, --sb-font-size, --sb-line-height, --sb-padding, --sb-ring, --sb-focus.

Theming

Presets: dark (default), light, dracula, matrix, tokyo-night, nord, gruvbox, catppuccin, github-dark.

<Terminal theme={{ background: '#1a1b26', foreground: '#a9b1d6', prompt: '#7aa2f7', cursor: '#c0caf5' }} />

Or override the CSS variables from outside:

<Terminal style="--sb-bg:#000; --sb-fg:#ddd; --sb-prompt:#0f0; --sb-cursor:#0f0; --sb-selection:#444; --sb-radius:12px; height:400px" />

API reference

Prop	Type	Default	Description
structure	FileStructure	{}	Virtual file system (copied, never mutated).
commands	Record<string, CommandHandler | CommandDefinition>	{}	Custom commands.
theme	string | Theme	'dark'	Preset name or colour object.
user / host	string	'user' / 'host'	Prompt: user@host ~ $.
promptStr	string	–	Replaces the whole prompt.
promptFormat	string | (ctx) => string	–	Prompt template with <user> <host> <cwd> <path>.
placeholder	string	–	Hint shown while the input is empty.
cursorStyle / cursorBlink	'block' | 'bar' | 'underline' / boolean	'block' / true	Caret look.
visualEffect	'none' | 'glow' | 'scanlines' | 'crt'	'none'	Screen effect.
animations	boolean	true	Turn all motion off with false.
fontFamily / fontSize / lineHeight	string / number / number	–	Typography.
maxLines	number	1000	Scrollback limit.
helpMessage	string | string[] | (names) => string	–	Replaces the help output.
notFoundMessage	string	–	Unknown-command text; <cmd> is the typed name.
disabledCommands	string[]	[]	Built-ins to switch off.
welcomeMessage	string | string[]	[]	Shown on start.
typewriter	boolean | number	false	Type the welcome message (number = ms per char).
windowStyle	'none' | 'macos' | 'linux' | 'windows'	'none'	Title bar style.
title	string	'Terminal'	Title bar text and aria-label.
syntaxHighlight	boolean	false	Colour commands, flags, strings, operators.
ghostCompletion	boolean	false	Faint command suggestion; Tab accepts.
persist	boolean | string	–	Save the file system to localStorage.
autoplay	AutoplayItem[]	–	Scripted demo (read-only terminal).
autoplayLoop	boolean	true	Loop the autoplay script.
typingSpeed	number	50	Autoplay typing speed (ms).
bootplay / bootSpeed	BootplayItem[] / number	– / 10	Fast non-interactive log.
readonly	boolean	false	Show output, no input.
autoFocus	boolean	false	Focus the input on mount.
mobileKeys	boolean	false	Show Tab / ↑ / ↓ / Ctrl+C / Clear buttons.
onchange	(fs) => void	–	File system changed.
oncommand	(line) => void	–	A command line was executed.
class, style	string	–	Container class / inline style.

The old on:change={…} event still works.

Server-side rendering

The component renders on the server (SvelteKit-safe); localStorage is only touched in the browser.

Development

npm install
npm run dev        # demo site
npm test           # unit + component tests
npm run test:cov   # with coverage
npm run check      # svelte-check
npm run package    # build ./dist

Contributing

Contributions are welcome! Please run npm run check && npm test before opening a pull request.

License

MIT © Yusuf Cengiz