skills.rest
mpsuesser
mpsuesserCOMMUNITY
Explore all skills by this author →
GitHub

effect-command-executor

Execute external programs with Effect ChildProcess and capture typed output.

22|1|Updated Apr 14, 2026
Search Tags:#process management#effect-ts#streaming output#scoped cleanup#childprocess#exitcode handling
One-click install
npx skills add https://github.com/mpsuesser/pi-effect-harness --skill effect-command-executor
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: effect-command-executor
Source: https://github.com/mpsuesser/pi-effect-harness/tree/main/harnesses/effect/skills/effect-command-executor
Command: npx skills add https://github.com/mpsuesser/pi-effect-harness --skill effect-command-executor

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Automating external command execution while preserving correct lifecycles, typed outputs, and deterministic cleanup in Effect-based code.

Core Features & Use Cases

  • Composable command construction: Build commands as AST values (template literals, array form, and option-tagged templates) and compose pipelines with pipeTo-style flow.
  • Typed execution modes: Capture stdout/stderr as strings, lines, or streams, or use process handles for interactive control and long-running tasks.
  • Scope-safe process lifecycle management: Ensure spawned processes are cleaned up via Effect.scoped, and use ChildProcessHandle utilities like exitCode, kill, and fd piping.
  • Use case: Stream a long-running linter or formatter output chunk-by-chunk while the process runs, then verify its ExitCode and fail with a domain error when it exits non-zero.

Quick Start

Use the effect-command-executor skill to run a command and collect its output as lines: Ask it to execute git diff output and return only the changed TypeScript files by using ChildProcess.make('git', ['diff', '--name-only', 'main...HEAD']) with spawner.lines(...).

Frequently Asked Questions about effect-command-executor

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I execute external shell commands in Effect with reliable stdout and stderr capture?▼

You can execute external shell commands in Effect safely by using the ChildProcess module to spawn processes and capture stdout/stderr as strings, lines, or streams while ensuring deterministic cleanup.

How does Effect handle process lifecycle and cleanup for spawned child processes?▼

Effect handles process lifecycle management by using Effect.scoped with ChildProcessSpawner, ensuring spawned processes are cleaned up automatically via Scope and providing utilities like exitCode and kill.

Can I stream long-running process output chunk-by-chunk in an Effect application?▼

Yes, you can stream long-running process output in Effect by using process handles for interactive control, allowing you to read output chunk-by-chunk and handle process cancellation or kill semantics as needed.

What is the best way to build command pipelines and compose commands in Effect?▼

The best way to build command pipelines in Effect is by constructing commands as AST values using template literals or array forms and composing them together with pipeTo-style flow before execution.

How do I verify a child process exit code and fail with a domain error in Effect?▼

You verify a child process exit code in Effect by using typed ExitCode comparisons after the process finishes, allowing you to fail the Effect with a domain error or PlatformError wrapping when it exits non-zero.

Related Skills

Explore More Software Engineering Skills→
spencerbeggsspencerbeggs
2

running-commands-and-tools

Execute and manage subprocesses in Effect v4 with typed combinators.

Community
Advanced
betalyrabetalyra
30

effect-uai-streaming-structured-output

Decode and stream schema-validated JSON objects from model output as JSONL.

Official
Advanced
mepukamepuka

effect-collections-datastructs

Expose Effect data structures for value-based structural equality checks.

Community
Intermediate
mepukamepuka

effect-resources-scope

Manage resource lifecycles with acquireRelease, scoped, and finalizers.

Community
Advanced