Cargo-Each

cargo-each: run a command over a cargo-style selection of workspace members.

cargo-each resolves a package selection expressed with the same selectors as cargo build, optionally narrows it with a small metadata predicate language, and runs a command over the result — either once per member (with placeholder substitution) or exactly once for the whole set. It exists to replace hand-rolled for-each-package shell loops with a single cargo-native, cross-platform command.

cargo-each ships as an executable only; it is a cargo subcommand, not a library dependency.

Installation

cargo install cargo-each

Usage

cargo each [SELECTION] [FILTERS] [EXECUTION] -- <COMMAND> [ARG...]

Everything after -- is the command template; cargo-each spawns it directly (argv, not a shell string) after substituting placeholders.

Selection (mirrors cargo build)

• -p / --package <SPEC> — select a member. Repeatable. SPEC is a package name, a name@version spec, or a Unix glob (tokio-*).
• --workspace / --all — select every workspace member.
• --exclude <SPEC> — drop a member (with --workspace). Repeatable.
• --none — explicitly select zero members (a no-op that exits 0).

When nothing is named the default is cargo default-members, exactly like cargo build; pass --workspace for every member. A selector that matches no member is an error, so typos fail loudly. A computed selection (for example a CI affected-packages set) is fed in as ordinary flags via shell expansion — cargo-each has no file or environment-variable source of its own.

Filters

--filter <PRED> keeps only members matching PRED; --exclude-filter <PRED> drops them. Both are repeatable: --filter predicates are AND-combined (kept only if a member matches every one) and --exclude-filter predicates are OR-combined (dropped if a member matches any one). Exclusion wins over inclusion. Predicates:

• lib / bin — the member has a target of that kind.
• dep:<name> — the member declares <name> as a dependency.
• metadata:<dotted.key> — package.metadata.<dotted.key> is present.
• metadata:<dotted.key>=<value> — that key equals <value> (numeric compare when both sides parse as a number, else string compare).

Execution modes

• per-package (default): run the command once per selected member, in name order, substituting the per-package placeholders below.
• --once: run the command exactly once when the set is non-empty (skip when empty), using the {packages} placeholder to inject the selection.

--keep-going runs every invocation and exits non-zero if any failed (default is fail-fast); --chdir runs each per-package command from that member crate root (its Cargo.toml directory) instead of the current directory — per-package mode only, so it cannot be combined with --once; --dry-run prints the fully-substituted commands without running them.

Placeholders

Substituted inside each command argument:

• {name} — bare package name (per-package mode).
• {spec} — name@version (per-package mode).
• {version} — package version (per-package mode).
• {manifest} — absolute path to the member Cargo.toml (per-package).
• {packages} — the cargo selection flags for the resolved set (--workspace for the whole workspace, else --package name@version …); valid only in --once mode and only as a standalone argument.

Using a placeholder in the wrong mode is a usage error. Only the tokens above are interpreted; any other {…} sequence (a typo, or a literal brace an argument needs) passes through verbatim to the spawned command — there is no brace-escape, so this passthrough is part of the contract.

Behavior

An empty resolved selection (via --none, or a filter that removes every member) is a successful no-op: cargo-each prints a one-line note and exits 0. This is what lets callers drop bespoke nothing-to-do guards. Otherwise the exit code is the first failing command code (fail-fast), 1 under --keep-going if any command failed, or 2 for a cargo-each usage error (unknown selector, bad predicate, misused placeholder).

Examples

Run a per-manifest tool over every library crate:

cargo each --workspace --filter lib -- \
    cargo check-external-types --manifest-path {manifest}

Run one clippy invocation over a computed subset, skipping when it is empty:

cargo each -p crate-a -p crate-b --once -- \
    cargo clippy {packages} --all-targets -- -D warnings