> ## Documentation Index
> Fetch the complete documentation index at: https://bun.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Global cache

> How Bun stores and manages packages in its global cache

Bun stores every package downloaded from the registry in a global cache at `~/.bun/install/cache`, or the path set by the `BUN_INSTALL_CACHE_DIR` environment variable. Packages live in subdirectories named like `${name}@${version}`, so multiple versions of a package can be cached.

<Accordion title="Configuring cache behavior">
  ```toml bunfig.toml icon="settings" theme={"theme":{"light":"github-light","dark":"dracula"}}
  [install.cache]
  # the directory to use for the cache
  dir = "~/.bun/install/cache"

  # when true, don't load from the global cache.
  # Bun may still write to node_modules/.cache
  disable = false

  # when true, always resolve the latest versions from the registry
  disableManifest = false
  ```
</Accordion>

***

## Minimizing re-downloads

When installing a package, if the cache already contains a version in the range specified by `package.json`, Bun uses the cached copy instead of downloading it again.

<Accordion title="Installation details">
  If the semver version has a pre-release suffix (`1.0.0-beta.0`) or a build suffix (`1.0.0+20220101`), it is replaced with a hash of that value instead, to reduce the chance of errors from long file paths.

  When the `node_modules` folder exists, before installing, Bun checks that `node_modules` contains all expected packages with appropriate versions. If so, `bun install` completes. Bun uses a custom JSON parser which stops parsing as soon as it finds `"name"` and `"version"`.

  If a package is missing or has a version incompatible with the `package.json`, Bun checks for a compatible module in the cache. If found, it is installed into `node_modules`. Otherwise, Bun downloads the package from the registry, then installs it.
</Accordion>

***

## Fast copying

Once a package is downloaded into the cache, Bun still needs to copy those files into `node_modules`. It uses the fastest syscalls available for this: hardlinks on Linux, `clonefile` on macOS.

***

## Saving disk space

Since Bun uses hardlinks to "copy" a module into a project's `node_modules` directory on Linux and Windows, the contents of the package only exist in a single location on disk, greatly reducing the disk space used by `node_modules`.

The same applies on macOS, with a caveat. There Bun uses `clonefile`, which is copy-on-write: the clone occupies no extra disk space, but it counts towards the drive's limit. Because the copy only happens on write, patching `node_modules/*` in one project can't affect other installations.

<Accordion title="Installation strategies">
  Configure this with the `--backend` flag, which all of Bun's package management commands respect.

  * **`hardlink`**: Default on Linux and Windows.
  * **`clonefile`**: Default on macOS.
  * **`clonefile_each_dir`**: Similar to `clonefile`, except it clones each file individually per directory. It is only available on macOS and tends to perform slower than `clonefile`.
  * **`copyfile`**: The fallback used when any of the above fail. It is the slowest option. On macOS, it uses `fcopyfile()`; on Linux it uses `copy_file_range()`.
  * **`symlink`**: Used only for `file:` (and eventually `link:`) dependencies. To prevent infinite loops, it skips symlinking the `node_modules` folder.

  If you install with `--backend=symlink`, Node.js won't resolve node\_modules of dependencies unless each dependency has its own `node_modules` folder or you pass `--preserve-symlinks` to `node`. See [Node.js documentation on `--preserve-symlinks`](https://nodejs.org/api/cli.html#--preserve-symlinks).

  ```bash terminal icon="terminal" theme={"theme":{"light":"github-light","dark":"dracula"}}
  bun install --backend symlink
  node --preserve-symlinks ./foo.js
  ```

  Bun's runtime also supports `--preserve-symlinks`.
</Accordion>