--filter (or -F) flag selects packages in a monorepo by pattern. A pattern is a package name glob, a ./path glob, a {dir} directory selector, or a ... dependency relation.
It is supported by bun run, bun install, bun add, bun remove, bun update, bun outdated, bun prune, and bun pm licenses. For package-manager commands, put the flag after the subcommand (bun install --filter api), since bun --filter <pattern> <word> runs <word> as a script.
Matching
Package Name --filter <pattern>
Name patterns select packages by the name field in package.json. For example, if you have packages pkg-a, pkg-b and other, you can match all of them with *, only pkg-a and pkg-b with pkg*, and a specific package with its full name.
Package Path --filter ./<glob>
Path patterns start with ./ and select all packages in directories matching the pattern. For example, to match all packages in subdirectories of packages, use --filter './packages/**'. To match the package in packages/foo, use --filter ./packages/foo.
Name patterns match the full package name (core does not match @acme/core; use @acme/*), and * does not cross /. Path patterns must match the workspace directory itself: ./packages selects nothing, ./packages/* selects every workspace directly inside it.
Directory --filter '{<dir>}'
A directory in braces selects every workspace in that directory or anywhere below it, resolved from the current directory. --filter '{packages}' selects everything under packages/; --filter '{.}' selects the current directory’s workspace and everything below it.
Dependency relations --filter 'foo...'
Adding ... to a pattern also selects workspaces related through workspace dependencies:
foo can be a name glob or a directory selector (...{./packages/api}). To exclude, ! goes first: --filter '!...foo'.
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bun install and bun outdated
By default, bun install installs dependencies for every package in the monorepo. To install dependencies for specific packages, use --filter.
Multiple --filter flags combine: everything matched by a positive pattern, minus everything matched by a ! pattern. A pattern that matches nothing prints a warning. For bun add, bun remove, bun update, bun prune, and bun pm licenses, selecting no workspaces at all is an error.
Given a monorepo with workspaces pkg-a, pkg-b, and pkg-c under ./packages:
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bun outdated displays outdated dependencies for all packages in the monorepo, and --filter restricts the command to a subset of them:
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bun install and bun outdated.
Running scripts with --filter
Use the --filter flag to execute scripts in multiple packages at once:
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packages/api and packages/frontend, both with a dev script that starts a local development server. Normally, you would open two terminal tabs, cd into each package directory, and run bun dev:
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--filter, you can run the dev script in both packages at once:
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package.json without a name can only be selected by a ./path pattern. If no selected package has the script, bun run exits with an error (pass --if-present to exit 0 instead).
Running scripts in workspaces
Filters respect your workspace configuration: if yourpackage.json specifies which packages are part of the workspace,
--filter only matches those packages. In a workspace, --filter can also run scripts in packages located anywhere in the workspace:
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Parallel and sequential mode
Combine--filter or --workspaces with --parallel or --sequential to run scripts across workspace packages with Foreman-style prefixed output:
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pkg-a:build | ...). Without --filter/--workspaces, the prefix is just the script name (build | ...). When a package’s package.json has no name field, Bun uses the relative path from the workspace root instead.
Use --if-present with --workspaces to skip packages that don’t have the requested script instead of erroring.
Dependency Order
Bun respects package dependency order when running scripts. Say you have a packagefoo that depends on another package bar in your workspace, and both have a build script. When you run bun --filter '*' build, foo only starts once bar is done.